My Father had the 4th gen nano (blue), man the little thing looked soooooo awesome i was watching the dark knight movie on it and i loved it! it's just like any nano(Had 3), they just drain alot of energy if you keep the screen on, so i recommend you keep the brightness a bit low and i bet your just gonna love it! Soooooo No Problem's whit the NANO'S! Except the random freezing's but its easy to fix and happens very rarely so no need to worry about that!
Now the "Ipod classic" that's another ball game since those baby's got allot of storage capacity and they do look nice even though there a bit BIG, but like i sed they do carry allot of stuff, so of course they are gonna be big! oh an never put one in you Book bag or back pocket and accidentally sit on it your might brake it's sensitive screen!(Happened to me sadly
)
it all depends on what you want. Size or Storage size!
I love small MP3's so i favor the NANO's any day!
Hopefully with all this crap ive seed it has helped you.