We have been to Camping Les Dunes at Les Sables d'Olonne. The overall area is lovely - the town is fairly chic, with plenty of places to have lunch. We never went in the evening, but I believe it is fairly vibrant. The hypermarket was nearby and very easy.
The Camping had standard size pitches. The overall site is small so nothing is too far from the centre. The pool complex is very good and has lifeguards. Baggy shorts seemed the standard swimwear for northern European men. There is a bar, ice cream bar, pool (of the billiards variety), pizza restaurant, shop (with fresh bread), launderette. There is evening entertainment every night, some amazingly good and others fairly cheesy. We didn't notice any noise on the site away from the evening entertainment, even when I was waiting up for my 16yo to come back at 2am.
We were with Carisma, whose pitches were in one area - mix of Brits and Irish. There were loads of Dutch people there too. Probably there were 5 or 6 tour operators using the site. Carisma provided children's clubs which were fine - children were happy to go there each day (mornings only, iirc). They also did some family activities, the highlight being the very boozy beach barbecue.
It is on the edge of a large beach, although far from the best beach in the area. It was good that you could just walk to it not have to pack for a whole day's outing. There is also a forest with good walking and biking trails (you can hire the bikes from the site), and plenty of children's play equipment on site.
We would be very happy to go back there if they had bigger accommodation (we took 4 bigger kids/teens with us).