I spent a lot of time on both this weekend. I have to say that I'm leaning to DP now. Batman was fun, and there ARE a lot of things to do. However, everyone just talks about the Worm/Freeze strat. I played a lot of different ways, and that did score better usually. Needless to say, if you're not playing for score there are a lot of modes, especially with the minor villains.
Deadpool was just cool! The repeatable left loop on the premium...the right ramp to the katana (which was butter on the machine I played)...the Snikt target...all of those made the game very enjoyable. I also liked the way the playfield seems "fuller". The left ramp, and the L'il Deadpool bank are low on the playfield. It changes the fan layout just enough to make it feel different.
I wanted to like BM66 more, but I just didn't.