Strengths: Mike Birbiglia did a great job as both the writer and director of this film. His direction was well done, while the writing was consistently sharp and moving. Each of the characters in the group feels completely formed. They're more like real people than characters, actually. The actors all brought it. Keegan-Michael Kay (Jack) was fine, while Gillian Jacobs (Samantha) steals the show. Her character gets a lot of great material and she does very well with all of it. It's the best work I've seen from her. Birbiglia (Miles) also acts and probably has the second best performance. The entire film works as a great look into the life of a comedian. It's not something that gets tackled in this kind of realistic light very often.
Weaknesses: It doesn't really work as a comedy. While some of the improve scenes made me laugh a bit, this is much closer to a drama. There are some flat out sad, almost depressing scenes. Though I appreciated how real the characters felt, none of them really came across as likable. Some parts of the movie also kind of drag, making this feel a lot longer than its 92 minute runtime.
Overall: Don't go into this expecting a bunch of laughs, because you'll be disappointed. Instead, understand that it is a character drama. The characters get well-rounded arcs for the most part and there's real emotion behind the stories.