You should really go see Fast & Furious 6 instead.
The conclusion to this raucous saga has been positively slammed by all who cover films for a living, as you can see for yourself in the following sampling of Hangover 3 reviews...
It's a "dull, lazy walkthrough" that has "a claim to be the year's worst star-driven movie." - The New York Times
Those looking for hilarity and hijinks with episode three will find the party is indeed over. - The Toronto Star
The first Hangover was good dirty fun; the second was dirtier, and less fun. But the third? It's just a chore - and no hair of the dog is going to make it any easier to bear. - The Newark Star-Ledger
The good news is that The Hangover Part III isn't a rerun like the second episode. The bad news is everything else. For all the promise of mayhem and WTF moments, the final episode hits you with all the force of a warm can of O'Doul's. - The New York Post
Young viewers looking for unbridled raunch will be sadly disappointed, and so will other moviegoers expecting more than a few wan chuckles. This picture is like a brightly colored balloon with all the comic air seeping out. - The Hollywood Reporter
The Hangover Part III gives off such a stench of creative decay that it hardly seems possible that even Phillips or his co-writers have any use for the movie themselves. - TIME
What was once fresh and fun is now just obnoxious and worn out. - Las Vegas Weekly