Wii-
pros: cheap, unique motion controls, a select few great games (mario galaxy, TP , mario kart, brawl)
cons: not so much a problem now, but earlier games expected precise movements to be detected with the wii's motion sensing (cod3, ew D:), meh graphics(if graphics actually matter to you.)
PS3-
pros: good graphics, bluray, some good games(idk, dont have a ps3)
cons:expensive and ?