Under pressure from the kids, I put my prejudices aside 4 years ago to go to Butlins, since then we have been back every year. Personally I don't like it, but the kids absolutely love it, so it makes it a great holiday. We use the pool and beach as much as possible and stay away the from the late night entertainment. My top tip is to book the premium food package. It is actually edible and allows you to spend your holiday enjoying yourself rather than cooking.
We have also been to Centre Parc's twice and a variety of static caravans, plus various places in Europe.
The kids have now had enough of going to Butlin's as it was getting a bit samey, so this year we are off to northern France in summer and Gran Canaria at Easter.