I saw this today. I really enjoyed the first one, It's a film that I can happily watch time and time again and still find it funny. I saw the second one and enjoyed it too, though it wasn't as good as the first.
I wouldn't say that it was terrible, but it wasn't great either. I really hope that they end it now. It needs to be ended.
They should have just left 'The Hangover' as a one-off film - it would have gone down in comedy history that way. Unfortunately, thats not the way Hollywood works and while part 2 had some funny bits (I haven't seen part 3), it wasn't a patch on the fresh and original first film.