I guess I like 'em both equally. =)
My favorite Hasbro lines are Transformers, G.I. Joe, Star Wars, and the Battlestar Galactica Titaniums (I've got multiples of every ship, and about 30 Mark II Vipers).
Favorite Mattel lines include MotU, the various DC figures (particularly Batman: TAS and related lines), M.U.S.C.L.E. and Marvel Secret Wars from back in the 80s, and I've bought a handful of Hot Wheels during my life.