DC Universe Online ($50 plus $15/month subscription fee) is not like other massively-multiplayer online games, even the superhero ones like City of Heroes or Champions Online. In fact, it owes quite a bit more to three-dimensional beat-em-up games with powers, like Marvel Ultimate Alliance, Crackdown, InFamous and Prototype. This is a good thing, as instead of hitting a key and watching as your attack happens, you're actively participating in the battle.
This arcade quality means that a good USB PC gamepad is wise, such as Microsoft's Xbox 360 Wired Controller. Though it's possible to play DC Universe Online with a mouse and keyboard, doing so feels like you're working against the design. Gameplay is combo-based, meaning that as you go, you'll be able to push different buttons in sequence to attack in a string, which opens up a lot of damage, area-effect spells, and fun things like that.
First things first, though: there's a lot of customization for your hero or villain as you start the game. From gender to body type to powers and ultimately which of three heroes (Superman, Batman, Wonder Woman) or three villains (Lex Luthor, Joker, Circe) is your mentor, there's a lot of variation. Regardless of what you choose, everyone has the same intro level: you're stuck about the evil machine Braniac's ship, and you've got to fight your way off. This intro level is designed to get you used to the controls and is very easy. After that, you'll be dropped into one of a few DC cities, such as Gotham City--and since DC Universe Online is very popular, there'll be other players everywhere.
DCU Online, unlike other MMOs, can also be played all the way through solo, or you can join another team. Team play seems more limited than in competitors' games as you can't see your teammates' missions nor make one of them your active mission; all you can do is follow someone and take their word for it that you're helping them solve theirs. Teaming up is most useful in the instanced group fights that launch from specific places on the map. These take some time to complete, so be prepared to have your schedule blocked out.
DC Universe Online is an MMO for casual MMO players, fans of the comics, and someone looking to test the waters for more complex games. Leveling up is frantic, and it's possible to hit the Level 30 cap in about a week to two weeks of six to eight hours a day. That's far less time than almost any other MMO. It just gives you more time to try on a different set of powers and a different mentor.