I wasn't sure what to expect going into this, as it is a film based on a TV series I didn't watch, with a plot that didn't exactly fill me full of excitement.
Thankfully it's greater than the sum of it's parts. Very funny throughout, with two likeable lead characters, which is a refreshing change from the current crop of more mean spirited comedy protagonists (Robert Downey Jr. in Due Date, for example).

Similar in style to Hot Fuzz (another plus point).

Pleasantly surprised.