Keaton is my fave Batman, his in-suit Batman, and his at home in private brooding Bruce Wayne were pretty much perfect. His public Wayne persona, not quite as good, though it was better in Returns (such as his scenes at Schreck's office).
Conroy voices both roles very well, better than any other voice actor that has had the role by a mile, but because of the medium he is working in, and the percieved audience he is working to, he doesn't quite have enough of Batman's scary edginess for my tastes, though he still does the gruff Batman thing really well regardless.
Adam West is just fun, like the show itself. Pretty much perfect for the show in question, but would never make a good Batman or Bruce Wayne in more serious conditions.
I actually like Bale's spoilt, slightly assholish Bruce Wayne more than I do his Batman, or at least I find it more effective anyhow. I just think he does a great job of selling that persona, though I'm not sure that they need to make the public Bruce Wayne persona so obnoxious such a 'rich brat' all of the time. His Batman is fine overall, but I think Keaton did a much more convincing Batman voice and persona, and I think Nolan over-processes the Batman voice too much on top of Bale's own growliness, which doesn't help either. In fact for me it actually makes him less threatening in an odd kind of a way. I still like Bale Bats, he's just not my favourite.
Kilmer was a pretty spot on Bruce Wayne, but personally I hated his Batman, it was just too light and jokey, and had no edge at all to it. You could make the argument that is the fault of the film in question though.
Clooney never had a chance from day one.
My views anyway.