Alright, I've played this game far too much to not have written my honest opinion on it.
BASIC SUMMARY: You are a superhero who's conveinently arrived to the world in times of crisis, and you (naturally) use your powers to help the general populace and occasionally assist the "Champions" themselves against greater threats.
-Supermassive customization system (Everything from tights and capes to with a lizard-face, tail and double-jointed legs)
-You can throw anyTHING at people, provided you have the strength to pick it up. Freight (Cargo) containers included.
-A wide and diverse variety of powers that you can choose from*, with many actually well-balanced "Archetypes", or pre-build powers to choose from as well. (See cons for "*")
-Tons of references to other sources when you pay attention.
-The ability to essentially create even the story behind your hero (Where'd they come from? Why do they fight for the common good? Etc...)
-You can create... your own rival! Your Nemesis will actually even be the cause of multiple missions.
-You can skip the tutorial and get right into the main world (after your first character that is)
-In-depth tutorial and tooltips for newbies, provided they choose to do them.
-A diverse amount of areas that you can choose to explore (You don't have to leave a zone if you don't want to, there's generally higher level foes available somewhere)
-Wide variety of unlockables. If you see an NPC using something, you can get it!
But, this game does, sadly, have it's problems
-Though you can skip right out of the tutorial, you always have to do the same starting set of missions every single time, and there's not much getting out of them. It can get a bit stale if you do it too often.
-Can get VERY grind-y! A lot of the good-quality items can take an extensive amount of materials to actually obtain, and potentially days or weeks to acquire. (This is true however for many MMO's, though, serously)
-MANY things are locked if you're not a Subscriber (Gold member). Free-form builds, where you pick your powerset, are only playable if you either subscribe or drop $50 into the game just for that. Many Archetypes are locked without Gold as well. (Total of 9 classes availible right at the get-go, which is few compared to the grand scheme of things.)
-Game has quite a bit of noticable bugs (But most of them are hilarious, like backflipping at hilarious speeds.)
-Nemesis system feels a bit tagged-on, just to say they have it.
I think I covered just about everything. There are times when I can't stop playing and will get hooked for a week, but then, you can actually set this game down for a time and come back to it again later.