I don't have much experience with massively multiplayer games like World of Warcraft. I just started playing that a few months ago, and it's going pretty alright. What really got me intrigued in the genre is DC Universe Online. So I'll most likely end up comparing those two particular games a lot.
I've only had the DCUO game for about a week, and so far I like it. I haven't had any moments where I thought, "Well, what am I supposed to be doing now" as I've had for WoW. I'm really digging the character creator, I've made half a dozen superpeople and will probably make a few more. Also the DC comics universe is something I enjoy, so flying around and fighting alongside Superman is awesome to me.
Speaking of the character creator, it's simple to make any kind of hero or villain you can think of. It's not as robust in the facial features as I'd like, and there are only three types of body sizes, a small, medium, and large choice. Which, if you're making a guy looks like a teenage boy, a full-grown man, and a hulk-like physique. If you are making a lady, it's the same model just scaled up or down depending on what you want. Once you get past that you can make your character into anything you can think of, similar to a copyrighted character, or make one up yourself.
The only real limitations with the character editor are with what they call "mentors". Being a comics based MMO there are two easily definable factions, hero and villain. There are many types of different kinds on each side, but in DCUO there are only three and they're the same for each side. The Superman/ Lex Luthor physical, Batman/ Joker gadget type, and the Wonder Woman/ Circe magic. It's too samey on each side. What if I want to be a Green Lantern, or have Green Arrow as a mentor. Or maybe I'd like be similar to the Scarecrow, or robotic like Metallo. I'm not saying there aren't ways and paths down on skill trees to be Hal Jordan, I'm saying I'd like the choice at the beginning. And what about Aquaman? What if I wanted to talk to fish?
And the lack of variety doesn't end there, every hero or villain you make, the first half hour is the same escape from Brainiac's ship, which leads directly into an odd point. Near the end of the level, you get to fight alongside either Superman or Lex Luthor depending on what you pick. And at that point you feel like no matter what skill tree you go down those enemies aren't that much of a threat to you. You're tearing through them left and right, but your comrade has trouble. Which if your fighting alongside Superman should never happen against those low-level types of foes. In WoW most of the races have their own different starting areas.
One of my complaints with WoW however is that sometimes, I just don't know what to do. I'll be in an area doing quests, then I can't find any more to do. Either there are and I can't find the guy with an exclamation above his head, or there really aren't any there, I think both of those have happened once or twice. In DCUO I've never had that problem, and I haven't really been running low on quests to do so far and the ones I've been on aren't that bad.
Which is another thing, I haven't seen a fetch quest so far in DCUO. I'm not saying they are bad, or that there aren't any in DCUO, it's just in WoW at any point I can be on five or six quests each of them are "collect x of random object". The quests in DCUO often times have multiple objectives to do in a line, ending in a "dungeon" where you fight a DC villain, if you're playing a hero. Instead of the back and forth doing one job at a time before a quest line ends. I know there are way more fun objectives in WoW than playing fetch with people, and I might end up not liking the structure of the quests in DCUO, but for right now I'm having more fun fighting Bane than a seemingly random bigger tiger.
Something WoW has that DCUO doesn't is a job system. In WoW, I can have a character specialize in something like mining or fishing, that can help benefit me and other players. I haven't found anything like that in DCUO.
Admittingly, I have done little if any actual multiplayer events in WoW. There's something about playing with random people online that never sits well with me. It's the abundance of assholes really. I mean, I have tried a PvP battleground in WoW, but unless I really want to just spawn and die while running around like a jack-ass I can't see myself doing many of these by myself. In DCUO there are things called alerts, where a group of players goes does a whole mission together with combined quest objectives. It's pretty awesome when you're not exactly sure what to do with an objective and you have three more pairs of eyes looking for that last computer you have to hack when your turned around and don't know where you are in the map.
I am having a lot of fun playing both games as of right now. I still feel like there's a lot I can do in both games before I feel I've reached the end. Given the subscription nature of both products, I might not keep both active at the same time though, I think the time off from either game will help keep them fresher longer. And so far I'm having a lot of fun in both.