Fast Five, no matter how much better it is than the previous four films in the franchise, is a pretty silly movie. It starts with a jailbreak that is somehow perfectly orchestrated such that they are able to wedge a sports car under a moving prison transport, get the bus to roll over about ten times without killing any inmates, and then rescue Vin Diesel and take him to Rio. Diesel and his gang then proceed to rob "the most powerful gangster in all of Rio" in the most preposterous manner imaginable while The Rock tries to track him down, killing anyone and everyone in his path like he's the Hulk.
The cinematic elements are fairly standard for modern action movies: quick cuts, shiny shots, and all the explosions, chases, and fistfights you can take. The movie often hides what is going on from the viewers for no reason other than to surprise them later, and you have to try especially hard to suspend your disbelief in this movie, but the screenplay contain some clever twists, especially with respect to the heist. The dialogue, however, is laughable. Vin Diesel's performance makes the script seem even more ridiculous, as he apparently has confused yelling with acting. The Rock, who I respect much more than in his early days, is not only the best actor in the film, but the best by about ten orders of magnitude. It's a very enjoyable movie that succeeds as mindless entertainment, but don't expect anything more than that.
IMDb link: http://www.imdb.com/title/tt1596343/