Most moves can easily be done w/a DB, and I see no real advantage of the KB in things like pressing and squatting. When doing one arm work like snatching or pressing, you're going to get an offset effect even w/a DB. However, the KB makes it much easier to do some of the conditioning work, like figure eights, tactical lunges simply because the handle is not inside the weight plates, and easier to grab. Also real easy to switch hands, not to mention it is a thicker grip, and some of the MMA types prefer that. Also, when doing swings, I just find them much more accomodating. Personally, I use DB's for the major basics, and do my swinging, and repition snatches, figure eights etc w/ the KB. I think it boils down to personal preference.