Of course, I haven’t yet completed it 100%, but I’ve done all the story missions (and got Super Hero/Super Villain on them all) and the two bonus levels.
It really is a great game, and so much bigger than Lego Indiana Jones. I do get the feeling some of the suits for Batman and Robin are a bit of a contrived device, and swapping characters and suits in Free Play mode is a bit of a chore as there are so many to cycle through, but overall it really is very good. Better than Lego Indiana Jones? I think, perhaps, maybe it is. Perhaps.