I haven't paid attention to bike stuff in a long time but I imagine all they've done is slight improvements to geometry and weight, I'm sure the clutches might be improved in the cassette but for the casual rider I'm pretty sure there's nothing huge...
Back in College I went to the local surplus auctions for fun (go figure) and would buy sections of pallet rack width of bikes/parts for like $20, sell some bikes to people that lived with me and took the rest to my moms, there's still a pile of junk parts and some stuff... My favorite bike I got there was a Nishiki Pueblo, went home for christmas break and took it home to be safe (Mom's in the country) and a bum stole it from in front of the garage! So from there I sorted through my junk and found a Raleigh frame and a random fork and scrounged for derailleurs and wheels and cranks and such, it's a nice bike but I need a suspension fork for it since there's not enough caster without but it rides fine... It's gotta be chromo or something, that frame empty weighs like 2 pounds...