TBH there isn't much in it, Win7 is more feature addition and advertising blitzed version of Vista. The only reason I upgraded to Win 7 was because I loved the home share feature (almost all other machines in our house had Win 7 on when purchased) and it only cost me £30 (student). Otherwise I would have stayed with Vista.
Performance wise and general use wise I see no difference at all.
Performance wise and general use wise I see no difference at all.