As I said, DCU is good if you subscribe. If you're playing f2p, you're limited. You're lowest priority for log-in queue, so at times you might have to wait a long time to even log in. And if you decide to switch characters, that starts all over again. Once you hit lvl 30, except for special events, missions you'll get bored with, and farming 4 and 8 man missions, there's not a whole lot to do aside from PvP and exploring to complete collections. You're also majorly hosed as far as in-game currency is concerned, because you can't do a whole lot with only 2k available to spend, no matter how much you have in the bank.
If CO didn't hose you as far as power choices were concerned, I'd probably be willing to try it again f2p. The limited costume choices and not being able to recolor powers doesn't bother me. But as things stand, there's not a single character that I had when I originally played that I could accurately recreate as far as powers selection goes. Midnight Crusader, my very first character, would be the closest, as he was purely munitions aside from having Regeneration. GhostMachine would be the hardest, because he had powers from 4 or 5 different powersets.
The only time I really miss CO is around Halloween, because I loved the seasonal event.