Colts because their D can COVER tight at the line of scrimmage, the thing B'more got killed by and could not do. Plus, Indy can pressure with their front 4 which is absolutely necessary if you cover tight at the line.
On offense, Luck seems to be one of those guys that makes plays when the S is hitting the F. And he seems to have the weapons, the skill people and they have the attitude. They were all getting pissed when Denver made that one 4th down at the beginning of the 4th (IIRC) just furious, players and coaches and I looked at the score, they're up two scores. Indy isn't there to give it a go as the new guys. They seem to be very much about getting it done.
They bounced back, right away, against Denver. They can run enough to put together drives. Special teams seems to be good enough.
Of course, on the other hand, it is Brady and Bellichick and that whole crew.
If I have to boil it down to one thing, it is that Indy applies pressure and covers man, tight, at the line. I can only guess the Raven's didn't think they could cover like that and it killed them. In the brutal reality of the NFL, if Brady gets in a few shots on Indy, they're going to be hitting him all game and that pays off in the second half. You can't let a great QB pick you apart. Baltimore did. Yesterday, Indy wouldn't allow it.
Indy wins.