I'll say one thing's for sure Batman does get the better writers you'd never see Batman get jobbed the way Iron Man does by the Marvel editorial staff. Like having his helmet get ripped off by Namor, his armor getting torn off like tin foil by Wolverine, or getting trapped in Spider Man's webbing, all while ignoring Iron Man's technical capabilities that prove to the contrary. It's hard comparing intelligence since most of these characters specialize in different fields, so saying that someone is smarter for being able to open portals to other dimensions as opposed to an uncanny knowledge of metallurgy is flawed.