Basically the shape: it's "thicker" and wider than the older/newest ones, if you're looking for portability (and that's what the nano is all about imo) those options are better.
There must be a reason if even apple took a step back in terms of design, don't you think
?
The price sounds really good, though, how many GB is that?
If you have the chance to "handle" it a bit and you get nice feelings you can disregard my suggestions, obviously
.
From a personal pov the taller/thicker ones "feel" way better.
p.s. latest version has some more fancy stuff, like the screen that is sensitive to rotation and you can change songs in random mode shaking the ipod. nothing fundamental.