I got my hands on this monster last week and it is amazing. The quality of the sounds, screen, keys, build of it is superb.
You can play any type of music on it, there isn't a best category as it has sounds for every type of music, eg. pop, rock, classical, indie you name it it's in there.
At the price they cost (cú5000 UK) it is obviously more geared to the serious studio user/recording or for the pro's who can afford one and dare risk gigging with it.
It's worth every penny though in my books, considering all of the features and more so now with the new operating system. I love messing about with the Karma settings, they are limitless.