Are we talking about the originals here? Or the entire line? Well, either way I think it's PlayStation. That's a loaded question though because what are you judging it by? Originality, exclusives, specs, performance? A lot of my favorite games ever were Xbox exclusives...halo, chaos theory, psychonauts, kotor... but the actual piece of hardware and controller were clunky and not all that revolutionary (even though there are fans now, at the time literally everyone preferred the S type). The scope and legacy of PlayStation in general though is just too great. (Good that you didn't include Nintendo though, would have been a much easier call)
tl;dr PlayStation
Japanese or American animation?