Pros: Addicting and fun TD game. One of the best I have ever played. Maybe a bit too easy at the beginning and maybe too hard at the end, but once you figure out(I suggest you read the help screens at the beginning of each map) how to use those towers, it is not impossible. Ads are not very annoying as you don't see them while playing.
Cons: Only thing that comes to my mind is that there is no online scoreboard. But then again, who cares.