I haven't tried OC. I just recently picked up machine polishing and started with IP and FP from CMA. I'd probably stick with Menzerna as, despite the dusting, I really like, but there aren't any West Coast Menzerna distributors so I decided to try out 4*'s MCC, which I can get from Patrick @ Excel Detailing (tasty candy with every order, service that's just as sweet.)
The reason why I've liked using IP (after I realized not to use too much product, thanks again Spoiledman) is that it breaks down very quickly and after a quick wipe of the all the dust, I can take a second pass. All accounts of Optimum products say they take longer to break down which isn't what I want. I suspect, though, that with the UDM going full power on an aggressive pad, anything would break down reasonably quick. Going after a single spot, I got the paint to be hot to the point of being uncomfortable to touch for too long. Yea I don't wanna do that again but I'm sure the UDM would make short work of anythign short of a really aggressive compound.
Which reminds me, I think what would be really helpful if someone who knows, would tell us what what's the most aggressive polish or compound a random orbital can easily handle?