Nice. MvC:I is still not pretty enough for me to buy, but maybe this move will encourage other fighting game devs to incorporate cross play into their games?
Good. All fighting games should be cross-play, since one can't argue there is an advantage of PC over console or vice versa (any advantage would be using an arcade stick, which you can do on any platform). Also the player population is critical for that genre, so the higher the better.