Like a lot of people, I'm a big fan of John Lithgow, who is a very versatile actor. He's one of a select bunch who are adept at serious drama and broad humor, as seen in his turn on "Third Rock from the Sun" and his hosting SNL.
This show isn't pretentious about the humor. It's broad and fast-paced in most episodes. If you don't like one joke, wait thirty seconds or so and we've got another one for you. The writers make use of a lot of devices to get the humor across, including some quick-hitting sight gags you need to watch for or you'll miss them. (As an example, check out the slogan for the health club in one of the episodes as the trial begins.)
Jayma Mays is a bundle of sexual tension in her role as the ambitious DA and is nearly as funny as Lithgow's character. Sherri Shepherd is great in a sometimes too small part. Overall, the cast is wonderful and seems to be having a lot of fun with the show.
I will say that I don't know if this is a show that has a lot of staying power, though, because it's hard to see where it can go after this first season. Still, it's a very funny half-hour that really is a lot different from most of what's on right now. The only show that takes the same approach to fast-paced, packed with jokes is "Angie Tribeca." It works for them and it works well for this show.