Although lacking in reliable E-frames and Y-Axis, the great thing about M.Striker in PvP is how versatile he can be. The standard combo is just XXXX + high kick (same with any M.Fighter, really), although once you get the hang of him you can pull off some neat out-of-the-blue shit. Lightning kick will reset enemies' air combo counter, which will be extremely useful in doing some insane damage combos. XX -> grab when opponents are on the ground to warp. F. Tornado Kick can be used to catch enemies in air off guard, which you can then transition into a combo. These are just a few tips, but there really aren't any specific combos when it comes to MStriker. Just mix in a Mountain Pusher here and there with some Close Kicks or Dragon Kicks to finish off combos. As for late game PvE, you'd probably be a lot better off with SD. Gearing her is way less hassle than MStriker, whose Chrons aren't very good unless you like gear switching. I'd argue that a very geared MStriker can be on par or even better than a very geared SD, though, but I'm not strong enough to verify that.