This is the best flash-based player I've ever owned. With 8 GB of internal memory, there is more than enough capacity for my favorite music, even at higher bit-rates.

I strongly prefer this player to the slightly larger Creative MuVo units. The U2 has a much larger and more legible display that provides more information about the mode, function, tracks, and settings. (In fact, some people complain because there's TOO much information on the display, but the display mode can be modified by the user.) The built-in lithium-ion battery charges in a couple hours and seems to hold a decent charge. The power output may not be greater than the MuVos', but it sure sounds like it's louder. You also get an FM receiver, bass enhancement, the ability to scroll your tracks and use play lists, and numerous other features missing from the MuVos. Since I was already familiar with the operation of the Cowon M3 player, I felt right at home using the controls of the U2. There was virtually no learning curve. The iAudio 7 also plays video files (must be compressed using Cowon management tool,) records from an integral microphone, functions as an alarm clock, and displays text files.

So, after experimenting with the MuVos and a couple other mini-players, I found that I should have just stuck with the Cowon products. This one is a winner.

FURTHER COMMENTS: It's been about six months and I have to admit that this is almost the ideal MP3 player for me. I'm not trying to pick on the iPod (these same observations apply to many MP3 players,) but the iAudio has three times the battery life on a charge, better sound quality, higher power output, the ability to play twice as many music file formats, and virtually no DRM limitations. The only reason I can see that you might want to buy a different unit (with the same storage capacity) is that you might prefer another GUI. So be it.

The D2 is a great media player, but it is not perfect. I'm not a big fan of touch-screens and the D2 is Cowon's first flash-based touch-screen player. In my experience, touch-screens are less effective than navigation buttons or hard controls, offer poor visibility when the user is trying to select a function, and accumulate fingerprints and dirt much faster. However, in the case of the D2, the trade-off for hard controls would likely have been a much smaller display. This is not to say that the touch-screen does not work well. I think that Cowon did a good job of implementing the UI and operating the unit is far more intuitive than with their 7 or M3 units.

With 16GB of internal storage and a SD/SDHC slot, you have plenty of room for media files on this thing. Switching between the internal memory and the removable memory is a bit more of a hassle than I'd like...you have to back out of the file browser to switch between them. I've only tried a 4GB SD card in the unit, but I've seen reports that it handles both 8GB and 16GB SD cards. I tend to run my Cowon players in a "Folder" mode, since I organize my media in separate folders by artist and album. The D2 takes significantly longer than the 7 to boot up after making any changes to the files, since it scans for new files and rebuilds its internal database. This is a minor irritation, but those few seconds of delay (sometimes as long as 30 seconds) seem much longer.

There seems to be a lot of debate on PMP forums about whether the D2 uses the same "hardware" (chipset) for the DAC/amplifier stages as the 7. All I can say is that they sound pretty similar, though the D2 may have slightly better transparency. As with all the Cowon players, sound quality is excellent and the 74 mW of output (37 mW/channel) is more than enough to drive most portable headphones. Cowon PMPs may not be audiophile-quality, but they consistently rank among the top few in overall sound quality. I also looked at the top-end Sony PMPs, which are ranked very highly in terms of sound, but went with the D2 because it played more file formats, had less-restrictive DRM, had better battery life, had a SD/SDHC slot, and cost more than $60 less. Many reviewers also pointed out that the D2 has much more extensive and flexible EQ/sound enhancement settings than the Sony.

And speaking of battery life, the D2's internal battery basically runs forever. A lot of people don't care for the Cowon products, but I've never read any review that didn't acknowledge that Cowon products are unmatched in battery life.

I normally don't watch movies on my PMPs, choosing to use my Palm PDA for that purpose. While the D2 has a smaller (320 horizontal pixels as opposed to 480 on the Palm) display, it is physically much smaller than the Palm, has better battery life, and has much better picture quality and sound. Cowon claims that the D2 will stream video at the (astounding) rate of 2000 Kb/s. I don't know about that, since I usually compress it at less than 1/10 that speed, but it COULD be true. Some users seem to have problems with converting video to play on the D2, but I simply use FairUse Wizard and have been very successful. You can encode the video using DivX, XviD, or any of several other encoders. A couple forums have commented that the video must be encoded at 320 horizontal pixels, but my D2 plays and displays 480 pixel videos just fine.

As with the other Cowon PMPs, the D2 plays OGG and FLAC files, as well as MP3 and other common file formats. It will also handle album art and lyrics. Puzzlingly, though, the D2 (as well as the 7) does not support permanent playlists. It has a Dynamic Play List feature that is not too useful, but I haven't seen any way to build permanent playlists. Fortunately, I don't use playlists much, but this seems to be an odd feature to be omitted.

OK, that's the important stuff. Some minor features of the unit include the ability to record and encode audio directly from a line input (using a special adpater cable,) the ability of the unit to play back through a standard NTSC TV (composite video,) and the inclusion of an FM radio, text editor, audio recorder, and two calculators. (Yes, you can actually go to a hotel and hook up your D2 to the video input of the room TV and watch your videos.)

This player is about the size of a pack of gum and its feature-set is very similar to the M3 described below. The unit is available in 512MB, 1GB, and 2GB capacities, but each is limited to only a total of 600 files or folders. Unlike some of the smaller MP3 players, this unit does not have the capability of being plugged directly into a USB port (see the MuVo units described below). You must use a mini-USB cable to connect to it and to charge it. Wisely, Cowon made sure this was a generic cable used for many other USB applications. You can buy a separate charger unit, but I'd recommend going to eBay and buying a 5VDC power supply/transformer with an integral USB connector. They're only a couple $$$ each. As a bonus, the U2 has a line-in connector next to the headphone jack, so you can actually record tracks directly from other types of players and audio sources.

I strongly prefer this player to the slightly larger Creative MuVo units. The U2 has a much larger and more legible display that provides more information about the mode, function, tracks, and settings. (In fact, some people complain because there's TOO much information on the display, but the display mode can be modified by the user.) The built-in lithium-ion battery charges in a couple hours and seems to hold a decent charge. The power output may not be greater than the MuVos', but it sure sounds like it's louder. You also get an FM receiver, bass enhancement, the ability to scroll your tracks and use play lists, and numerous other features missing from the MuVos. Since I was already familiar with the operation of the Cowon M3 player, I felt right at home using the controls of the U2. There was virtually no learning curve.

So, after experimenting with the MuVos and a couple other mini-players, I found that I should have just stuck with the Cowon products. This one is a winner.

I did a lot of research before I bought this unit. I am very pleased with many of its qualities and a bit let down in some other areas. The M3 consists of a main unit, with a metal skin and low-profile controls, and a remote control/display unit. The remote can be unplugged from the main unit and you can just use the main unit by itself, but you will not have any display to see what you are playing or to select songs. I've only used it in this way once or twice. The main unit has a 20 GB HDD (some units have 30 GB) and this HDD is transparent to the user when you connect it to a USB port on your computer. It looks just like an ordinary external HDD, where you can drag and drop files, change names, delete files, etc. USB connections are made either through the furnished cradle or through a snap-on adapter (also provided) that converts the USB connection to a standard mini-USB port.

The remote unit is a nice feature of this unit and I suspect it contributes to the durability of the M3 by reducing the need to move the main unit around to manipulate the controls. The remote has a relatively small LCD display, but it is quite legible and shows just about everything you would want to know about system status, file type, elapsed time, and so forth. The little roller switches take a bit of getting used to, but stick with it and they'll soon become second nature. Another advantage of the remote is that it can be replaced completely separately from the main unit. If your control goes bad or the LCD is damaged, just buy a replacement unit and plug it in.

I really like the fact that this player can handle several different types of music files, including OGG format files. There are absolutely NO DRM controls on this unit. I use a freeware application, MediaMonkey, to interface with the M3. The Cowon iAudio software is just not that good. The amplifier section is pretty powerful and the sound quality is excellent. My experience with battery life has been outstanding. The unit will play for at least 12 hours on a single battery charge, even at high volume

Now for the problems: One big problem is that there is some data noise in the audio output under certain conditions. When using a high-quality headphone amp, I can hear a "ticking" sound during low-volume passages. It was inconsistent and it took me some time to figure out that it is related to the scrolling of the song or album title across the display as a file plays. If it's a short title, there's no scrolling and no sound. If it's a longer title, there's scrolling and "ticking". If you speed up the scrolling, the "ticking" speeds up. I was able to reduce it slightly by adding some resistors to the input of one of my amps, but it is still there under circumstances. The only other complaint I have is that it is more difficult to find accessories for this player than for Creative Nomads or Apple iPods.

This is a nice player with one huge flaw: It will not create or use play lists. This is really frustrating, as it has so many positive features. The basic unit is a 1GB USB flash drive with an integrated player and FM tuner. When you plug it into your computer's USB port, it is assigned a letter just like any other drive. There are no DRM restrictions. After removing the unit, you slide it into what is basically a battery holder (uses one AAA battery) that provides power for the player. You can then slip this assembly into a transparent plastic holster that will clip on your belt. While the unit only has 1 GB of capacity, this is plenty if you rip your music down to smaller (lower quality) MP3 files. The MuVo plays files in file name order...again, no play lists. You can skip a file or even a whole folder, but that's about it. The controls are pretty intuitive, though I seem to have a problem turning mine on sometimes. I have to hold the button down for what seems like ages before the splash screen shows up. FM radio performance is surprisingly good. In fact, I've often said that I would have bought the unit just for its FM reception, even if it didn't also play MP3 files. Very handy for working in the yard. Plus, I got mine for free from Staples using the bonus $$$/rebate plan they have.

This is very similar to the MuVo TX-FM described above. It is basically a USB flash drive (either 1GB or 2 GB) that slides into a battery holder. Unfortunately, it does not come with the case/belt clip that the TX-FM includes and lacks the FM radio feature. Like the TX-FM,it is not capable of using play lists. Furthermore, it is a little more complicated to navigate your folders on this unit than on the TX-FM. Audio performance and battery life are very similar. The V100 is more rectangular than the TX-FM, too. All things considered, I prefer the TX-FM to this unit.