Has anybody used this system for anything other than a super hero game?
I'm doing it right now; I'm playing a mostly fantasy/slightly sci-fi campaign with a couple friends using M&M. So far it has worked well, at least for us.
We pulled it off as lower powered by self-imposing the following points:
1)
Lower starting level and slow advancement: our characters started at Power Level 5, enough to get heroic characters while avoiding being supers; by the time the campaign ends, we might reach PL 10 at most. The fact that we prefer well rounded characters - spreading our PPs instead of concentrating them in a few strong powers - also helps.
2)
Pre-emptive checking with the GM about which powers can be chosen: this needs both the players and the GM to have a clear idea (and a clear agreement) on what is appropriate for the setting; for example, our characters are a martial artist with lots of feats, slight super-strenght and a little bit of control over shadows and an animist who summons animal totems to do his bidding: these concepts are supported within the setting, but time travel, significant teleporting capabilities or astral projection would have been rejected, just to name a few. Of course, what the powers represent must also be setting compliant: if you have energy blast(fire) in a fantasy setting, chances are it's your trusted fiery dart spell, not your built-in cybernetic flame thrower.
3)
If you are the GM, be ready to be surprised: while certain powers are clearly out (time travel is often banned for a reason), be ready for the players to come up with some very creative explaination on why a certain power can be fit in. Also remember that certain non-blatant powers may just represent powerful yet mundane abilities.
A last note: unless you aim for a game where - like in a superhero one - characters always rely on their powers to solve things rather than on mundane abilities, it's better if you use the 1 PP -> 3 skill points option, like we did.
I hope this was of help.