My money's on Bioware. Being a multiplatform developer is often a significant advantage in March Mayhem; granted the Escapist has a very large PC gaming community but Bioware is very popular on the PC so even if they split the PC vote with Mojang if they get most of the PS and XBox community behind them they'll win hands down.
Bioware is also a very popular dev on the Escapist. As I've said before I think they would have won last year if Valve wasn't benefiting from the anti-Zynga surge. This isn't to say that Valve isn't well liked as well, but I do think that Bioware has the edge.
It also looks like Bioware simply has the votes. They won against Blizzard with 24,036 votes while Mojang beat Valve with only 16,661. I really like Mojang and I may even vote for them in the finals (I'm undecided) but I think they'll have an uphill battle if they want to win here.