I've lived in Burbank for several years and never been to see the tonight show. I decided to take my wife and some friends and made ticket reservations.
The bad: The wait to get in is a little long and you have to stand outside. We also had to park about three blocks away. Next you walk to another line and wait some more. Once inside, the seating seems to be random, so there is no guarantee you will get a good seat by arriving early.
The Better: After being seated for about one half hour, Jay comes out and talks to the audience, takes a few photos with lucky folks near the front rows and generally talks and answers questions. A while after that, the show actually starts. Our show featured nobody interesting for me personally, but the audience seemed to enjoy.
The whole process from arriving to leaving took more than 4 hours, and to me that is too much time to give for the results, buy hey it's free, so no big loss. It's one of those things you probably should do once if you get a chance, but don't set your expectations too high.