I think any show is in the eyes of the beholder. When I go to one of the large shows I am in awe of all the beautiful quilts that are hung.
The vendors are usually pretty good, but that is not the main reason I go to the shows. I want to see the quilts and can spend days just looking at the quilts. Always buy the DVD (when available) to go back and remember what the quilts look like.
As for vendors, I have a friend who vends at the big shows. All the work bringing things and setting up a booth, then being on ones feet for days with little or no chance to rest just amazes me. Unless a person has actually vended at a large show, we do not have a clue how exhausting it is. I've watched her booth for a bit while she gets something to eat or just takes a small break. I know I couldn't do it for days.
I don't think anyone can imagine the thrill of coming into the show and seeing that your quilt has moved to the "winners area". Its happened once for me and the feeling is just unbelievable. There is usually a designated area where the winners are hung, usually somewhere in the middle of the show area.