It really kindof depends. For some people, 8:30 is a little late for dinner. In our house, we're not usually ready to have dinner until at least 7pm, sometimes later, so I don't expect 8:30 to be a big problem for us. Plus there are lots of options for pre-dinner snacks if needed.
You won't miss any more or less with the late seating vs. the early seating as I recall. Yes, there some activities that take place during the late seating, but likewise there are activities that take place during the early seating as well.
I think meeting another family is part of the fun. Our kids and their kids were roughly the same age range, and they seemed to hit it off pretty well.
From what I've read, the rotation you'll get frequently seems to depend on the age of your kids. I don't see one rotation being any better than another.