I enjoyed the tone and setting of the movie. It did a very good job of balancing being heartwarming and funny, often at the same time. Michael Cera can get a bad rap for playing the same role in all his movies, but he did a great job in this movie, even if it was his same role over again, and it was interesting to see him play his alternate personality throughout the later half of the movie. The movie didn't try to make any points, it didn't try to be starkly realistic, instead it just tried to present a fictional story about how far someone will go for love and let it go from dark when needed to absurd when needed.
The rest of the cast did a great job too and almost all of the actors seemed to be cast perfectly, making their characters come alive and not just feeling like they were actors playing a role. I also could sympathize with Nick's character and some of his feelings. Of course this is purely subjective, but it made me like the movie all the more.
Overall, it wasn't a life changing movie. I don't think it will be considered a classic movie 10 years from now. But I came away from it smiling and would definitely watch it again and recommend it to anyone.