Winners are grinners, and everyone won, in some way. The actors, the audience, and the characters.
As others have written, this is not your typical Jack Black, Steve Martin or Owen Wilson movie, although Owen Wilson doesn't stray far from some of his other characters.
The romantic interest (Rashida Jones) was delightful, and (not having read the book) I thought that she was secretly going for a Big Year herself, so the plot was twisted in my mind to that effect (not a bad thing). Anjelica Huston has a cameo that adds quite a bit to the comedy.
Overall, I thought it was a great movie which presents the everpresent challenges of attaining your dreams, balancing your obsessions / hobbies with the important things in life - which are yours to determine - not anyone else.
Funny, not irreverent. Beautiful, and not overpowering dramatic, but with some drama.
Well-worth watching on the big screen.