I feel Ma and Lang Lang are quite different musicians. Yes, Ma does have a showmanship, but his expressions are compatible with the music he's playing, not like Lang Lang, sometimes I feel like he's just putting on a show that has nothing to do with the music, which can turn people off (of course there are also a lot of people who love him just because of that). I think Ma is much more mature and 内敛.
As for appearing at public affairs in China, I don't know how often Ma actually shows there, but probably because he's doing this "Silk Road" project that is promoting Chinese/Eastern culture through western music.
Well, Yundi Li is coming to CSO this December, I'll want to see in person what different style he has!