I use the default controls, except I've switched LB and X so I can charge shots in combos.
The "problems" with the X360 controller are greatly exaggerated. Holding and releasing the RB for combo purposes has not been an issue for me at all. What has been an issue is applying pressure to LB while doing instarevs, and I don't know if that's a X360 controller issue, or just a problem with my hands, as it's something I never did on the PS2 controller in previous DMC games.
edit: I hold the 360 with the same claw technique I use for the Dualshock in previous DMC games. Index and Middle finger of each hand curved around the top. My middle fingers are more straight than they would be with a dualshock to accommodate the height of the triggers relative to the face of the controller, but otherwise the grip is the same.