Lots of great options for playing music from different sources
340265
I love this little sound bar.  I call it "little" because it's smaller than the other "TV Bars" I've seen out there, but it's still fairly big to give you good sound.

I love that it has adjustable controls for bass, treble and that it has a large variety of inputs (AUX, Input, SD Card, Bluetooth, etc).  Also the built in FM radio is a huge plus (It even comes with the antenna). So many people forget about the plain old radio sometimes!

The sound was sort of blah out of the box, but I fine-tuned it with the remote and it sounds perfect to me now.

The only thing that might become an issue in the future is that you need the remote to do certain things, and because it's so small I'm worried my kids will lose it.  Otherwise, this is a great little unit!  HIghly recommended.
4432257
This is a great little MP3 player, but much more than that. You can read ebooks on it. You can watch videos. You can record -- my son uses it to record his band, and I use it to record classes I teach for upload to my online courses. The quality of the sound is amazing. For us, this one feature makes the T.sonic 850 enormously useful, and it's extra nice that it also functions as an MP3 player and ebook reader.

It's a stylish little player, and it comes with its own protective case. It's easy to use, and convenient to carry.

There is one flaw: it isn't possible to look at a list of songs or files and choose among them. You have to scroll through, or just play the whole thing. For me, this is acceptable. I like to make a playlist for a workout or a trip and listen clear through, and I'm happy to make my music choices on the computer. My kids felt differently, though. If you can live with that flaw, this is a great multi-use device.
2729070
A collection of song arranged to be easily played while sounding great.
1003038
Great variety of sounds for the price! Worked best for me to pick and adjust one of the delay/reverb combo options and leave it there when performing live. Best to use in conjunction with other pedals. Changing the battery can be a pain so use an a/c adapter!
3884276
covers a wonderfully wide range of styles of music. Wish each demo track could be longer but, I realize, that then there couldn't be as many tracks on the CD as there are so it is a trade off. I found I needed to slow the tracks down in a music editing program to get some of them, as some were too fast to grasp initially... for an intermediate like myself. I also used the music program to loop the tracks to hear it more times in a row. I like it over all.
4103704
Easy to set up. Nice choices for streaming music, especially from Amazon!
2865454
Highly reccomend, great sound, lots of channells
4042582
Works very well and very useful for different activities or just listening.
4601144
As an MP3 player/jukebox, this player performs very well, almost reaching the spot of ipod replacement.  It supports MP3, WMA, Ogg Vorbis, and FLAC.  Ogg Vorbis is another lossy codec, performing quite a bit better than MP3 and WMA.  FLAC is a lossless codec, about 1/2 the size of a WAV file.
It does not include an FM radio, voice recorder, or remote.  The first two may or may not be absolutely essential to you; they weren't at all for me.  A remote *might* be in a future release, but don't buy this product expecting one.
Sound quality is superb, as it has a powerful headphone amp and also comes across clearly (check out head-fi.org's portables forum if you don't believe me).  Besides the usual EQ presets, the Karma also includes a 5-band parametric EQ, which I'm told is quite special for a portable audio player.
The stated battery life is 15 hours I believe.  It comes quite close to that, though I haven't been making accurate measurements at all (I just let it play and forget about the battery).
The included dock is quite unique, featuring both RCA lineouts and an Ethernet port for connecting to your network and transferring files.  I don't think any other player includes an ethernet port or network connections at all yet.
The included Rio Music Manager isn't quite like iTunes, but it does have a really easy interface and is more than acceptable for transferring your music tracks.  You should use something else to listen and rip your tracks though, as separate encoders will give you much more flexbility anyway.
One innovative feature is the included Rio DJ, which autogenerates playlists with a certain set of requirements.  No other player has anything quite like it, as far as I know.
The menu interface is clean and concise, and is quite easily navigable with the Riostick and scroll wheel.
One thing of importance with this product: you absolutely *must* get the latest firmware (1.68 at time of writing) to prevent from having the reliability issues some other people mentioned here.  The latest firmwares are supposed to have fixed on the hard drive issues some people have been having.  I would highly recommend purchasing an extended warranty (as I did) to preserve peace of mind.  Rio's 90day warranty is woefully short for such a pricey object.
I don't know anything about Rio customer support, but their *engineers* consistently hang out on the Riovolution.com forums, which ends up making it a wonderful site for any Rio owner.  They listen and respond to constructive feedback/questions occasionally.
One such example is that the rio engineers have recently confirmed that USB mass storage support (the drive shows up as a removable drive in Windows/Mac) is forthcoming in a future firmware release.
Overall, I would highly recommend this player to anyone looking for a great, dedicated MP3 player that almost equals the iPod in functionality and ease of use.
1485783
You might have a hard time finding one at a reasonable price, but it delivers a world of possibilities. The distortion modes sound somewhat cheap but the expression modes are spectacular.
2385524
Works great, sounds great, and has some nice basic options such as random play.
2886983
A well organized book which provides a wide spectrum of different pieces from various composers. Easy to play and it is very user friendly.
408655
Bought one for my wife a few months ago. She's loved it, and now I've got one as well.

My requirements are:
  - must sound great
  - support easy drag-and-drop (USB Mass Storage interface), ideally including GNU/Linux systems like Ubuntu
  - should be easy to use, easy to find and play a particular song.

This device fills all those needs. True, it's not _as_ easy to use as would be an iPod (which, however makes up for its ease-of-play by making it retardedly cumbersome to transfer the files, requiring you to use their proprietary iTunes software). But since you can choose how to arrange the directory hierarchy, you choose how the songs are organized.

As another reviewer has noted, traversing the directories can be a little painful, given that you have to scroll up through the titles to reach the parent directory link. Also I've noticed that it can be difficult to tell which song you've selected when you are including the artist and album name info in the display: you have to hover the cursor on the track before it displays the whole name, and it scrolls slowly enough that it will actually snap back to the player screen before it's finished displaying the rest of the title - and then you have to scroll back to where you were. I imagine both the time to snap back, and the information displayed for tracks are potentially adjustable; I haven't gotten to investigate yet.

I can't comment on the product life; some of the other reviews suggest trouble there. We've only had hours for a couple months/a few weeks respectively, but so far so good, and at this price I'm not terribly concerned about it.
1265994
This contains a lot of diverse music which actually is a good sell point.  All very well recorded.  Since I am into box sets now, this is a great box to have included in my collection.
4748667
Love that I can find the music I like to listen to at a reasonable price
3550555
This product is very user friendly. It enables me to play any type of music I want. I especially love the different skills I can add that are fun and exercise your memory. I am very happy that I purchased this product.
4414593
This unit has it all from legacy formats like cassette and CD to slipping in a memory stick filled with your downloads. The playback is great for a compact system and the battery power makes a versatile unit. The remote control nice when the unit is plugged in.
  This unit is pricey but a great value because if its quality and versatility.
  Cold beer, sunshine and a quality music source defines summer for me.