DC Universe Online, or DCUO, is a massively multiplayer online role-playing game based on the DC comics universe - you know, Superman, Batman, Lex Luthor. That place.
I hope I didn't blow your mind just there.
DCUO is kind of a tough one to call, as there's good and bad about it. So allow me to illustrate how I feel about it with a segment I call The Good, The Bad, and The Ugly.
The combat system is amazing: intuitive, actually involving movement and strategy. DCUO is one of the few MMORPGs I've ever played that actually made me feel like I was playing a real video game. The only other MMO I've played that had a system nearly this good was Maple Story, which is fundamentally flawed in entirely different ways. Even City of Heroes, my all time favorite MMORPG is basically the same as all the others: stand still and press a button whenever your recharge runs down.
The powersets are amazing as well. While there may not be very many of them they all have interesting and exciting powers. I actually looked forward to learning my next ability and wondering what cool thing I was going to be able to do next, as opposed to most MMORPGs I've played where my main concern is how good my build is going to be.
Of course, the story is good too, especially for a free MMO, which isn't surprising when you consider the writing staff at work here. The head writer is longtime DC writer Geoff Johns, whose works include Blackest Night, Brightest Day, along with a handful of Batman, Hawkman, Green Lantern, and Flash comics, among others. Along with him are a team of other greats, including Marvin Wolfman, who created -among other characters- the Teen Titans, Tim Drake (aka the third Robin), and Blade. Voice talents include Mark Hammill as the Joker, James Marsters as Lex Luthor, Wil Wheaton as Robin, and Adam Baldwin as Superman.
They also had Tracy Bush, who did the voice work for all the murlocs in World of Warcraft, so there's that too.
I should also mention that the graphics aren't terrible, though they really just don't do it for me.
I mentioned before that my all time favorite MMO is City of Heroes, which brings me to my major gripe about DCUO: the customization. Don't get me wrong, I'm not saying that DCUO and CoH should be held to the same customization standards just because they're both about superheroes, but really, come on. The body customization is basically non-existant. You have three options for build, each with three sub-options for size, and you have no control beyond that. You can't even change your face, which is particularly upsetting since you look like a hideous goon.
As for costume options, the "lock style" option where you can lock a piece of your outfit's appearance to remain the same regardless of your equipment is a nice option, but the costume options are just so damn limited that it's not like you'll be likely to find an outfit you really like anyway.
As I hinted at before, your powerset options are extremely limited as well. This is primarily the fault of the story -your powers come from "exobytes," small robots that contain all the powers of the DC heroes and villains- so you're only allowed to have powers that established DC heroes have. So since no DC hero has, for example, wind powers, neither can you. The lack of options for your powers is even more upsetting than the lack of appearance options.
The PC version...
Unlike most MMORPGs, DC Universe Online was originally designed to be played on a console, specifically the Playstation 3. The PC version, as a result, is...not so hot. It's not particularly stable, especially on lower-end computers, and the control system is fairly difficult to get used to with a keyboard and mouse.
KR Rating:  Good
I can't call this anything less than good when it has so many talented people putting in so much hard work to create such and impressively promising whole. In the end, it's also impossible to call it great when it's so flawed and limited. So it gets a rating of "good." It's not bad, but it could've been so much better.