I don't think I'm too far off your level Paul2 and I went last year. Absolutely loved every minute and felt I got an awful lot out of it.
Day one, I'll admit, I almost wished I hadn't gone as I felt out of my depth, and as the worst skater there felt a bit useless, but by day two I realised everyone there had their strengths and weaknesses, and what I was good at other people weren't so good at, and vice versa. I enjoyed the next three days immensely.
The main thing I got from it was a load of different ways of thinking about things, different ways to try things (different arm/leg positions for example, which often helped with things I'd been struggling with), and I came out with my edges a million times better and more controlled through doing different exercises (which were also fun).
I also felt I benefited greatly from the off-ice stuff - stretches and strengthening exercises mainly, which was knowledge I took with me and still use to improve myself.
The final day we played a lot of games, which really help your confidence, but I think the bit of advice I'd give if you're thinking of going is, you really have to be willing to go for it and put your all in, and be willing to try things you might normally be afraid of. And be willing to be absolutely cream crackered by the end.
Oh, and there are no barriers. Literally.