i agree that marvel is, for the most part, more believable, but what really bugs me about it is that, with XMen, it's as if all mutants have the same disease, that can be cured with the same hypodermic for everyone. i mean, how would it “cure” someone with wings? they would have to be surgically removed, not injected w/ anti-mutant crap! and how does what takes away magnetic powers also cure a laser-eyes ability? they are completely unrelated!
anyhow, even though i could go on for a while about that, i will simply skip to my last point. i think DC characters are mostly cooler (aside from certain specific heroes).