Board Thread:General Discussion/@comment-7823447-20140810191254/@comment-4651179-20140810192900

Considering Marvel still hasn't shown a single Hulkbuster armor which has actually busted the Hulk, I'd say the Hulk.

If you need any evidence, in Iron Man vs. Hulk #4, Tony deployed the Heavy Duty Armor and fired all its arsenal to the Hulk. It did nothing. The next panel following one of Hulk throwing a punch at Tony? The suit completely demolished.