Hi,
We stayed at Val de Bonnal for about 10 days in August 06.
The site was great. Easily up to the usual Castels standard. The only problem with noise was that once a week they organised a 'disco-swim' at the pool. I wouldnt have liked to have been pitched near the pool on that night! Went on till about 10pm if I recall.
We did encounter some problem with flooding but that was the summer when the whole of France spent the entire summer under water (or so it seemed). Lots of people were giving up and going home due to the weather - it rained for about 4 days solid. When the weather cleared it was great. Day trips to Germany and Switzerland were possible (if a bit long).
The pool is great and the lake on site is good for dinghys and inflatables too.
Just be prepared to cover large distances once you leave the site as all the attractions seem to be fairly widespread.