I do them about 3 times a year.
Haven - yorkshire (caravan had mould in it, site was huge, too huge and we got ill with rotavirus)
Parkdean - cherry tree great yarmouth. Really nice. Caravan was dated but club house etc was small enough to be personal but enough facilites. Area was good if prepared to venture out on trips.
Parkresorts - st minver cornwall. Tiny clubhouse, pool etc but set in woods so nice for biking etc. Loads in the area and lovely caravan.
Parkresorts - shanklin isle of wight. If you stay here you get to use the next door site too so far more variety. Excellent caravan although you cant park your car next to it. My favourite site yet as soooo much to do on the isle of wight. Im going back in may. First time ive revisited a site.
Lake district- cant remember the operator but big site lovely big modern site, tons of facilities with a childrens farm on the same road. Nice stuff to do in the area, beautiful place to visit but perhaps no good for pram pushing etc as lots of hill walking etc obviously.
Trecco bay- parkdean. Fantastic site. Only time i havent used it as 'just a base'. Tons in morning for preschoolers, kids club and decent entertainment not just character shows but outside acts etc too. Great restaurants, amusements etc. Loads to see in wales too.
Butlins- minehead. In the sun booklet its not advertised as butlins but as 'minehead' 'bognor' or skegness but it is butlins for cheaps. Accomodation worst ive ever had and prob cost the most in initial outlay but best value as everything on site is free bar the food,amusements and drink. Fair rides are free, shows are free and go on all day. Best value by far.
Also did one near weymouth and that was amazing for the area but i cant remember where i stayed. That time we got an owners caravan and it was nicer than my house. Beach etc was fab. I'll try to find out where it was if you interested in that area.
Although they are 9.50, you do have to pay for min of 4 people so for me in a family of three im on the backfoot. I take my own bedding to keep costs down and although you cant usually dodge entertainment passes make sure you only pay for those your using. Im always charged for 4 and have to remove one. Do upgrade your caravan if you can afford to in spring/autumn stays so you get heated bedrooms.