"It all depends on who is playing. With Roy, I always win, at least against friends(I don't play tournaments). But with Marth, I hardly even win. I suck as quick characters, and that is what Marth is. Roy, on the other hand, is slower, but much more powerful. I'm better at that. "
No, tiers dont change on who is playing, Marth is still better than Roy in every way even when you play, you just don't know how to use Marth.