We stayed with Canvas at a site up the road and walked through this campsite to get to the beach every day
Pros:
You are RIGHT on the beach
Lots of different restaurants on site, on the beach, which were great value (had to book a table though).
On-site entertainment
Some of the vans had Air-Con, TV, Dishwashers etc.
Port Grimaud is walkable, and a great place to visit.
Water Taxis to ST Tropez etc available
Excursion leave the site
Loads to do.
Monaco etc are in easy reach
Cons:
It is a HUGE, VERY cramped site, we were there in the Summer Hols & it was heaving.
It is Very noisy by the beach and entertainment areas - all night.
The beach is VERY crowded
There is NO swimming pool (which my kids prefer - the Canvas site had an OLYMPIC pool & Waterslides).
The chalets etc on the beach have constant traffic walking past.
The whole area is a traffic jam - takes ages to drive anywhere - get a boat!
Personally, I wouldn't stay there, but other review sites have people returning every year.
We have stayed at La Carabasse in the LAnguedoc - lovely site and walkable to beach, but takes 10-20 mins through a vineyard.
Le Vieux Port in Gascony is a 5-10min walk - direct access to sea - but Atlantic coast so very wavy (surfer heaven).
CARISMA holidays are all direct access to beach if you want to check them out.
Or, I can recommend some on the Vendee - sea not so warm, but get there in a day??