We've been to Siblu - Domaine de Kerlann in Brittany.
It is a very good site, with a well-equipped central area.
They had an children's programme and evening entertainment, which was generally very well attended. The pool complex was excellent, and there were lots of playgrounds dotted around.
Our mobile home was very good, clean and well-equipped, but we were disappointed with the plot. We got the biggest (family of 7) and top-spec, which was fine for us (the weather was good so we were never cooped up), but the plot was small and scruffy - perhaps this was compared with neighbouring ones where the owners spent the summer.
The area is fantastic and we tended to go out each day to a different beach, but we came back to the camp mid-afternoon for pools, football etc. We ate early evening and toddled off to the entertainment.
Overall, we were happy with it at the time. However, the following year, we discovered Centerparcs in Holland for about the same price. There we had a huge villa and were sheletered from bad weather (which we really needed).