Hey there. I have a Rio Karma and I love it. Its battery life far surpasses that of any of the Ipods (16 hours with 128kbs mp3's. I get about 12 hours with everything at 192kbs Ogg Vorbis), and it features gapless playback, which was pretty important to me; I hate the pauses inbetween tracks mp3's have. It plays FLAC files too, if that hasn't already been mentioned. It might not be quite as "slick" as the Ipod, but I paid to have a great functioning player with lots of options, not just one that looks cool.
If there is one problem, it seems a lot of people have experienced HD failures with them. Luckily (and knock on wood) I haven't experienced any problems, which is great, cause I bought mine from a seller in the US before they were available in Canada, so I have no warranty. Not sure if the HD failures were an issue with early ones, because I don't hear about it much anymore, but I'd suggest going for an extended warranty, cause the the Rio warranty is only good for 90 days.
If you have any more questions about it, feel free to ask.
