The lead gives an amazing and charming performance. James Gandolfino is impressive too, and they are both very believable. The direction and editing are wonderful, all so smooth and out of the way, focusing very much on the characters. It's all blessed with an amazing script, a rather unusual story (fresh), quality humor, and one of the best on-a-date moments in movie memory.
The issue with it is that the second half doesn't feel as solid as the first, and the whole thing doesn't feel like it has good re-watch value. It feels more like (a really good) TV series, something like Girls.
It was an interesting discovery that the director responsible for this one (Nicole Holofcener) also made two other movies I love: Friends With Money and Please Give. For that reason, they deserve a revisit, more so than this one :)