Sidmouth, in short, is brilliant! The atmosphere is great. It's a pretty big festival, so there's something there for everyone. Lots of concerts, ceilidhs, more specialised dances, song and music sessions, workshops, and great big shows in the open air Arena Theatre. The latter consist of international dance shows (lots of different teams from all over the world) and sometimes concerts. In previous years Oysterband, Natalie McMaster and Stockton's Wing have done evening concerts there.
The camp site is about 15-20 mintues walk from the sea front. The Arena Theatre and showground, the Concert Marquee and most of the small workshop and session venues are in town. All of these are at most within 10 minustes ealking distance of each other. However, two of the major venues: the Bowd and Bulverton Marquees are out of town. The Bulverton (where a lot of the workshops and ceilidhs happen) is next to the camp site, a few mintues away. The Bowd is about 20 minutes walk from the camp site. But fear not, there's a frequent bus service available.
There are lots of shops in town, but there are also food stalls near all of the major venues and lots of stall at the Arena Showground.
I've been going for the last five years and it's great fun!
Hope you enjoy it.