Depends on what your perception of "better" is. In terms of raw effectiveness, Iron Man outclasses Batman in every way. Batman is limited to stopping street level crime, and while he does a great job of it, Iron Man tackles bigger problems on a global scale.
On the other hand, one could certainly make the argument that Batman's intentions are more noble. He genuinely believes in protecting Gotham City, so no one will ever have to go through what he did. Iron Man, on the other hand, does what he does out of a mixture of seller's remorse and a love of joyriding.
I think they're both great heroes, really. I couldn't pick just one.
On the other hand, one could certainly make the argument that Batman's intentions are more noble. He genuinely believes in protecting Gotham City, so no one will ever have to go through what he did. Iron Man, on the other hand, does what he does out of a mixture of seller's remorse and a love of joyriding.
I think they're both great heroes, really. I couldn't pick just one.