A:AnswerDefinitely the sound. The quality is overall better, especially with the spatial audio it allows for you to listen to your music while blocking out outside noises. I have about all generations and the 3rd is the best.
A:Answerreally it is just a matter of prefference...
and what i mean by that is that the ones with the gel peice may fit and feel better make a way better sound...
buuut if its me telling you what i think?> i think the higher verions are better in terms of sound and longer battery life but i love my third gens they work great for the two years i have had them till now