It amazes me how much people overrate Bisping.
The idea of him KO'ing Rich (or anyone) is one of the most ludicrous things I've ever heard.
That being said, while I love Rich he is definitely past his prime and his chin isn't all that sturdy anymore. I think he is a more powerful and versatile striker than Bisping but Bisping holds in the edge in technique and speed. Cardio I'd say they are about even but Bisping did gas in the third round of his fight with Sonnen and looked like hell against Mayhem (who just happened to look worse).
I'd still say Rich takes a 29-28 decision.