first, i would disagree your definition of XCM as "well rounded" yes they do incorporate different things, but how many people who do exclusive XCM do you see do two handed cuts.
but as to my preference, i actually enjoy doing a lot of both, there are certain cuts in both i dont care for, but the majority of ones i dont enjoy are found in XCM because i find they tend to flow a lot less. Its for that reason as well as just stylistically that i prefer Cardistry. I find that going from pandora, to molecule, to a sybil in the rain combo flows much more organically than putting a Cobra in anywere. just my opinion.