I originally bought a Neo about a year ago, because I didn't think it was really any different than the empeg, but the fact it used normal desktop drives was attractive (and by looking at *only* that terrible product comparison page, I'd probably still come to that conclusion). Now, a year later, I can tell you the Neo is not worth the metal it's molded from.
Before I even start, I should say $400 is very deceptive. In the end, I ended up paying about $800 total (due to the fact I had to buy a whole bunch of extra [censored]).
My first dissapointment came when I found out it wouldn't work with the IDE controller on my motherboard. I don't know why. Tech support doesn't know why. Nobody knows why. I had to go out and buy a $50 PCI IDE controller card just to get it to connect. I don't have a weird, off the wall motherboard either, it's an Abit Athlon motherboard, and works just fine with everything else.
The second dissapointment came when I found out you couldn't hot swap. That meant I had to reboot if i wanted to connect/disconnect the neo.
The third dissapointment came when I discovered the 'joy' of the buttons. Put simply, they are useless. Hope to god you don't lose your remote, or you'll never be able to control the thing.
The fourth dissapointment came when I realized you have to have a bay to play music. That means you can only play music in your car, unless you shell out another $90 for a home bay. Even then, you can't bring it over to a friend's house and plug it in.
The next dissappointment came when I tried to install it in my car. As others have stated, the neo is an odd shape. It wouldn't fit anywhere. I ended up putting in ot top of my dashboard with double-sided sticky tape. Real classy, I must say. The wires danggling off it were a nice touch. Oh, did I mention I had to get a new stereo too? (which is something i was trying to avoid in the first place by getting the neo over the empeg).
I finally got it installed, and more problems arose. The software is crap. The random is completely not random at all. It's hard to find songs due to the fact there is no searching, and there are no playlists. Add to this the fact that it would simply lock up for no apparent reason. It would be playing, then it wouldn't. Only solution was to take it out of the bay and put it back in (to reboot it). Not too bad if it's on your dash, but good luck if it's in your trunk.
The materials are *very* cheap. The metal ended up bending (warping) from being inserted/removed too much. I had to take off the cover to get it to slide into the bays. The display completely sucks (and no, it doesn't just suck compared to the empeg, it sucks compared to everything) It's a 4x20 LCD screen. Hugo's original mp3 player thing had a cooler display imho. The fact that it uses desktop drives, while sounding cool at first, is actually a bad thing. Desktop drives were not made to be moved around, and cars tend to do a lot of moving. Most people suggest putting a laptop drive in there and using a 2.5"-3.5" converter.
Oh, and don't bother taking these complaints to tech support. They don't care; they already have your money.
To make a long story shorter, I ended up selling all my neo stuff on ebay (I only got about 1/8 what I put in) and bought an empeg. I've never been happier. Installed it in about an hour, and have had to major problems. If it were impossible to get an empeg, I would have gotten a Creative Nomad, or RioVolt (or iPod, but they weren't out at the time).