Have you guys seen Shooter? Mark Wahlberg was great in that movie! There have been several others which he's done that have impressed me as well.
The Rock is OK, but I find it a lot harder to take him seriously, but I think either choice would have been decent for TF4 as they both work well as action movie leads/heroes.
Either way, I'm just glad that the lead isn't going to Shia again. He's a pretty funny guy, but 'funny' isn't what I'm looking for in a big summer action blockbuster.
I am Alpha and Omega, the beginning and the end. I am that which is, which was, and is yet to come.
And you will know my name is MEGATRON when I lay my vengeance upon you!