I don't get the critic hostility to the show at all. This is one of the easiest shows to like on TV right now. It is generally really funny, and when the characters decide to cut each other up it is hilarious. Erik Griffin should get at least a supporting role in a studio comedy movie off this show. I can't figure out what it is about Clark Duke, but he is really good at playing the annoying smartass that has just enough self-awareness to be interesting rather than a caricature.
Melissa Leo's part isn't that difficult, but she nails it. I thought Ari Grayner was a really good actress the first time I saw her in Nick and Norah's Infinite Playlist. She went off the grid for a while, but this could re-start her career. Jake Lacy is excellent too, The whole cast is solid. There is no weak link.
The characters are all screwups, so every plot twist is completely credible. One of the things I like the most is that the show doesn't try to be more than it is. It is a show about a bunch of struggling comics at a dingy LA night club in the early 70's. There is no big grand theme, it is just a story about a bunch of borderline losers dragging themselves through life.