PS3 performance seems fine to me (i.e. 30fps like nearly every other console game). Just fought a not-so-microchu in one of the FATEs with a ton of other people around and it was just as responsive as when nobody else is nearby.
My concerns are with the 720p resolution and the TV-sized UI, the targeting which is a pain in the ass, and the awkwardness of using hotkey bars made up of trigger+dpad/face button commands. With DCUO, you're limited to six abilities plus consumables and clickies so it's not an issue. This game seems to have as many abilities as a WoW-style MMO and that could get really annoying at high level. I can just plug a USB keyboard into my PS3 because it's on a desk and connected to one of my LCD panels, but I don't think that's an option for most people. Besides, if I wanted to do that there's no reason not to just play it on my PC that should be able to max the game out easily.