Vader dominates him. Obi Wan is the master of a style that just happens to be the best for the situation he was in, knew Anakin's moves inside and out, fought on hazardous terrain suitable for exploiting Vader's emotional turmoil, and of course heightened said turmoil via his presence. Despite all that he was still on the defensive for most of the fight. And I'm not convinced that Ulic is Obi Wan's match or superior with a blade.