We just got back yesterday from WDW and agreed as a whole family that Turtle talk was a must-see (me, DH, DD(9) and DS(7)). They have moved it to a larger theatre that seats about 150-200 people, and strongly encourage all of the kids to sit on the floor at the front. This makes Crush able to see them all and interact with them easily, and the kids who were there at the time were well-behaved and absolutely fascinated by Crush who could see and communicate with them personally. It did make for some difficulty to find our kids when we were all dismissed at the end, but my kids are old enough that I wasn't worried. I would have been much more concerned if they were under 6.
Crush was so funny that I think the adults in the audience enjoyed it at least as much as the kids. If you remember when the Muppet Show had inside jokes for the grown-ups but some funny parts for the kids as well, this is very similar.
The ride in the clamshells is just OK - worth doing once, but only if there isn't much of a line.
Enjoy!