There are better ways to spend your time than playing DCUO
The lack of variety is what ultimately brings DCUO down. Pretty much the only thing you can do is fight. The exploration and player interaction is kept to a bare minimum. At first the combat will feel engaging because there is no auto attacking, but soon you will notice how the game simply isn't challenging at all. You'll be going from one zone to another without even bothering to look what your skills do, mashing random attacks the whole way through. The game simply won't offer you a reason to care.
DCUO does deliver on brainless action, but the whole RPG element is pretty shallow. You can pick a few powers to fight with, but most of them seem all the same which don't offer any real strategic play, you just use them in a random order and you win. The quests are very repetitive, you'll be defeating thugs and saving civilians wherever you go, so playing the game will get old much sooner than you will hit the level cap of 30.
Character customization in style is pretty neat, but you cannot really make a legend out of yourself. You will be doing the exact same things the other players are as well, repeating the boring repetitive missions over and over until you reach the maximum level, and if you already haven't, stop playing it at that point.
There is some fun to be squeezed out of this free MMO, for a weekend or two at the very least, but the 10 hour download probably isn't worth your time. The client is 17 GB in size, and you cannot download it in the background, so you will have to leave your console connected the entire time.
At it's gameplay core, this MMO isn't all that different from the usual asian farm-fest MMOs, and since it lacks a lot of features to keep you busy, you're better off playing some other feature rich and smaller in size MMO out there. It's hard to imagine anyone who is not a complete DC nut playing this game for longer than a couple of sessions.