While I still find Jeff Dunham hilarious (excluding personal distaste for the style of his new tv show), I found that if you've seen his specials, you've seen his standup. Any time I laughed hard it was usually improv on Jeff's behalf or because he was cracking himself up by making the guitar guy (who seemed high but was hilarious himself) laugh as well.
I don't remember leaving with side splitting pain from laughter, but I still had a good time and the crowd was very into it. If you really like Jeff Dunham, I think you'd enjoy the show, but if he's a casual enjoyment, I wouldn't recommend this experience to you.