Over the years we have tried many combinations of company/site/van 
Depends on number/ages of your party and what you need.
Matthews cheapest van is VERY small, but surprisingly well equipped, eg had fitted mozzie nets on windows so could sleep with window open. We discovered them one year when we thought a holiday was out of the question, but got 2 weeks in late August including fast crossing ferry, insurance for car & us etc for c£900. It is way much better than staying in a tent anyway!
There largest van is HUGE and very nicely fitted (but obvioulsy costs more). They have limited sites, and none in that area though. Great for Brittany/Vendee.
Thomson Alfresco was Top Class, Air conditioned Huge van in prime location on a site that suited us perfectly. Pricey though.
We have done SIBLU more than any other (from when they were Haven). They have never let us down, good range of van layouts and competitive prices.
El Delfin Verde was a great site but quite remote so you had to drive everywhere (but direct beach access and good supermarket on site). It has a HUGE pool.
The best entertainment we ever had was at La Sirene. We had Lion King & other musicals in French with English songs! Hysterical, but worth watching if you like that.
La Carabasse has a great beach and you can walk into the village with lots of restaurants to choose from. Lots to visit in the area if you have a car as well. Another large pool. We have stayed there at least 3 times. It is owned by SIblu so if you have kids the kids clubs are huge and well run, plenty of staff for each age group etc.
HTH