This might seem weird but I liked Clooney as Bruce Wayne, especially his scenes with Michael Gough's Alfred. The Batman parts were difficult to watch and don't get me started with Batgirl!
I remember Clooney saying in promotional interviews for B&R that he figured it was a long time since Bruce's parents had been killed, so his Batman was kinda over it by now. Hence the laid-back and urbane portrayal of our favourite driven vigilante.
That should have tipped me off...