We went last yr as we were in the area... rather disappointed in the # of boats in the show. OK if you are interested in one Mfg and they have what you are looking for there.
Boat shows are like fireworks. Once you've seen the biggest, all the others look small. Still, I'd say you look at who is showing and if it's something you're interested in could be great. I'd personally enjoy a less massive show. I just looked at the vendors and boats and I see that it could be interesting for many people. If I was near Charleston and liked boat shows, I'd go. I wouldn't travel across the country for it. Here's a link to the boats being shown.