Serignan Plage is a big site, set alongside the beach, with lots of facilities. Some parts of the site are looking a bit tired, but there are some super pools towards the back of the site. Some pitches adjacent to the beach are very sandy, and quite small, but the ones towards the back of the site are larger and have more cover. The beach is good, but is right next door to a naturist beach - in front of Serignan Plage Naturiste site (the sister site of Serignan Plage) and the naturist area does tend to 'mix' with the 'normal' beach next door and the pools have separate hours of use by each site - but if you're happy about this it's no problem.
The beach can be quite windy so make sure you take wind-breaks. The sea is lovely there - we've used the beach quite a lot in the past, and stayed at Serignan Plage a couple of times on our way further south.
The site is quite a way from the nearest bars and restaurants - at the end of a one-way lane system - and the immediate area isn't the prettiest, with agricultural fields (melons and tomatoes) and 'terrains de loisirs' with sometimes dilapidated mobile homes on their own plot. However, the little town of Serignan is nice, there's a Super U about 5 miles away.