We went there in 2007 with DS (8 months) and DD (2.5) at the end of June.
Summer 2007 was pants weather-wise, but the site was lovely and quiet, facilities good, and the beach nice.
However, beware of Atlantic winds! On a windy and rainy day (and there were a lot of them last year...) it could be a bit grim. Takeaway is excellent; shop v basic but a supermarket only a few minutes away off the site.
The beach is across the road, but you have to cross the sand dunes, so it is no good for a pushchair. The beach doesn't really have any facilities, so poos etc have to be buried in the sand dunes and nappies carried back.
The site is on a road of campsites, with not a lot else around.
This year we went to La Garangeoire. It's inland and in the middle of nowhere, but the beaches at Les Sables D'Olonne with facilities are 15 minutes away by car. It is a lot less windy there, and we are going back in 2009 and have booked already.