I figure if you're a group on the go, counter-service would be better. But table-service gives you the chance to sit, relax, and visit before you head back off into the parks. Also, with table service, you're not constantly doing a head count and trying to find Uncle Charlie. 
What's been your experience?
Personally my family tries to LOOSE Uncle Charlie. 
I think as long as it isn't busy in the parks, counter-service could be a good option. But if it's busy that's a nightmare.
I think that Counter Service would be good..especially at places like Sunshine Seasons or Cosmic Rays..that way there is something for everyone.
Bella
Hmmm, good question. We have never done a big group but I almost think Table Service would be better. Then you know you are all sitting together, etc.