The graphical differences probably aren't even noticeable. Sites just mention which one has better graphics to appeal to fanboys (who are a big part of their readership). Let's face it. If you're in the middle of fighting 10 different thugs, or taking down The Joker (or whatever), you're not going to be caring about minor graphical differences. I never did.
Controller, well, I think it's great on both platforms. It's up to you. The exclusive content with The Joker is appealing, but weighed against the reasons you listed for the 360, it might not be.
However, I'm getting it for the PS3. Wanna know why?
This game is just made for the PS3. Everything about it. The Dark Knight, Batman, in this dark atmosphere. Blackness all around him. It just suits the PS3. Plus, in my opinion, the PS3 boxart for the game looks way better. And I like trophies more than achievements now (yeah, hate me for it, they're just better).
