I have a Nomad Jukebox 3 (only 20 GB), and I find it pretty good. Here are some ot the good things:
It has capacity for 22 hrs play with two batteries, which are user-replaceable. They're expensive enough on the Creative site (the batteries, I mean), but I got a second Creative battery at a local electronics shop for less than half that.
The navigation is handy enough, though I find it really is playlist-dependent, but then I guess they all are when you're dealing with at least 5000 files.
It has a host of in/out connectivity - optical and analogue line in, direct recording from a mic or from the wired remote radio (this has to be bought extra), as well as 2 lines out, which means you can hook it up to a 4/5 speaker system. Combine this with the wireless remote that comes with it and you have a nice way of using it as a stereo for parties or whatever. I have to admit though that I have never used most of the recording facilities, apart from the wired remote radio...
The sound and volume is good
It's pretty robust - I once dropped mine on the stairs, which it proceede to bounce down joyously, nearly giving me a heart attack - but it's fine!!
Some bad points:
It's heavy and quite bulky. It's about the size of a cd walkman, but twice the thickness. I think this has to do with the connectivity facilities.
20GB is becoming a bit of a tight squeeze, and my MC Library is not that big (ca. 6000 files). I can't get them all on there, so a well organised and tagged library is essential... Playlists, playlists, playlists! Especially smart ones! However, I'm in Ireland where everything electronic costs a fortune, so if you're in the home of the brave, the free and the cheap, I guess you'll be aiming for more than 20GB!
Finally, I have a big problem with the fact that the radio recording feature on the wired remote is limited to 10 minutes. I'm not 100% sure about this, but I think it is the case. My wired remote started acting up, and I haven't replaced it yet, (though Creative were very obliging when I reported the problem - I just have to send it off and they'll send one back...), so I wasn't able to fully check it out.
Anyway, hope that's of some use to you... Oh yeah - I really don't like the software that came with it, and bought Notmad Explorer from Red Chair Software for $20, which is really good and they keep improving it. Also, when any remaining issues with MC 10 and the Nomad are sorted out it will be a great combination with the Nomad...