Recs.
Updated
Specs
Pros
Pro Manages to balance characters of vastly different power types
Characters are built by expending Character Points on abilities, skills and advantages, and by choosing powers and complications. To balance the characters, the game imposes certain restrictions on what's possible based on game's chosen power level.
Pro Allows for quick character creation through the use of archetypes
M&M includes a variety of archetypes that players can base their characters off of. There are 15 archetypes to choose from. For example, there's a speedster archetype for Flash-like characters and shapeshifter archetype for Mystique-like characters, etc.
Cons
Con Rather complicated especially 3rd edition
Too worried about balance such as will/fortitude which is not realistic or doesn't even simulate the comics.
Con Requires lots of suspension of disbelief
Because characters like Superman and characters like Catman are balanced by the game to be comparable in strength it may be difficult to suspend your disbelief.