We went to one near Salou in Spain 3 years ago and it was absolutely superb. I can't quite remember the name but might We paid about £700 - including flights - for a week in May. I thought there would be a catch, but there isn't. The holidays are just superb value for money full stop.
The accommodation is decent enough - clean, modern, spacious and had a nice patio area outside to sit on. The kitchen had a fridge, cooker in and we had no problems cooking breakfasts etc and keeping the drinks cold! The beds were comfy, clean and we all slept well. The shower was clean and modern too.
The family loved it as it was really chilled and the park was very well kept. They are a cross between a large caravan and like a lodge - they are very nice. The whole place was spotless and they obvious spent a lot of time cleaning up, keeping the gardens well kept etc.
The pools were really good with waterslides, diving pool and a paddling part for the young ones. All the activities on the site were really cheap as well, something like 1Euro for crazy golf. I can't remember all the activities but there was a LOT to do on the site - kids entertainment, arcades, crazy golf, kids clubs at night, tennis, swimming, climbing frames and swings etc. The food and drinks at night were really good value as well. The whole place had a great atmosphere and there was loads to do. Kids absolutely love it and it's very, very safe.
The park we were on was next to the beach and about 15 minute walk from our lodge and the beach was immaculate and hardly anyone on it.
We booked to go to another one the year after, but Covid struck. We will definitely go back again and 100% recommend it.
Hope you have a good time!