Bammer was probably a bit easier to work with as Vader worked stiff. In ring, they were about equal in what they could do with Vader doing it at a heavier weight. In the Bret Hart DVD, Bret picked a match with Bam Bam as one of his favorites and talks about how he was really underrated.
A real fight? It took Bruce Baumgartner to take the NJ HS wrestling title from Bammer. Vader was a really big dude among really big dudes. If Bam Bam got in his shots early, I think he takes it.