Guess I have to disagree. I thoroughly enjoyed it. Just about every moment. I thought it was the best movie of the summer...by a decent amount.
Yes, the bridesmaids dress scene was vulgar - the best thing about it was that it was women doing it. Basically trying to stand up to the idea that only men can do vulgar comedy (I mean in the Hangover when they were getting tasered, that was sophomoric as well, so were numerous scenes in American Pie, Animal House, Stripes, you name it...only this time it was women).
I thought the scene for the Paris party was spot on. People do stuff like that - seriously. And it was great having a character call them out on it.
I loved the scene on the plane. Great, great stuff. I loved the very end after the credits.
But for me, the best part is that despite all the slapstick stuff, this movie felt real. People reach their mid 30's and feel the pressure to get married, and the pressure from their friends getting married and moving on. I know a ton of women like the main character (and men as well), who feel they can't win, even when winning can be right in front of them.