Pros:
Perfect murder sandbox, very open and diverse environment, the game goes back to it's root of Blood Money like gameplay, with heavy focus on environment interaction and many ways to kills. The changing environment and various paths increase the replayability of the levels.
Story wise the game is quite good with contracts to kill and a bigger storyline behind the scene, which keeps you interested in the overall game progress, the challenges and the contracts made this game even more exciting.

Cons:
Elusive targets doesn't reappear, even if you buy new copy once missed they are gone.
A few glitches, most of them patched.

Overall:
A must have game, even if you haven't played previous game in series this game will pull you in.