Now I will say I have a lot of love for Marvel Heroic Roleplaying, more than the next guy (unless he's the guy writing the Plot Points blog), but MHR has a distinct flavor that does a great job emulating comic books, but over the long term tends to start to feel bland. While I own it, I haven't played Icons, but I suspect the same thing with that game as well.
Does Champions have its problems? You betcha. It's got eight million ways to screw with the rules and build over-powered PC's (another reason I hate the internet sometimes). But with the right players and the right mindset? It's a great game.
Now for a true confession. I can not "get" Mutants & Masterminds. Other people love this game. I get the feeling that is the literary heir to Champions, so to speak. But something about the rules doesn't click with me. It's not that I dislike the rules, I just am having a tough time wrapping my head around them. Maybe I'm getting old and crotchety or something.