I took my Dad to see it this afternoon as sort of a belated Father's Day present. He really liked the first one and I think he enjoy ROTF even more.
I liked it, I'm not even going to lie the first time Prime was on screen I got chills. He's the best part of the movie for me. A lot less human characters than the first which was nice. Soundwave was voiced perfectly, and of course Cullen as prime is just awesome. Prime's swords were one of favorite aspects, he did some serious damage with those not to mention his guns. I thought Sam's roommate Leo was pretty damn hilrious too.
Minor nits:
-language (c'mon this is a movie based off a kids toyline)
-cheep laughs (dogs humping, pot brownies, jockstrap, etc.)
-Skids and Mudflap (hated them

)
-Robot chick, didn't care for that subplot. Way too "Species".