We have been to two in Holland.
We have been to Het Vennenbos near Eindhoven (summer 2003). It used to be a CenterParcs so has the fantastic pool. It is very close to the Belgian border and there are lots of things to do in the surrounding area. There is not as much to do on site as a British CenterParcs, but it had a Children's farm, play area, lake with sandy beach and maze. There was also a Children's Club and Children's entertainment but that was in Dutch so we didn't bother.
We have also been to Stroombroek (summer 2002) but that was before it was owned by Landal. It was good as well but if I remember rightly the pool didn't have any areas that dd (then 4.5) could stand. She was happy enough bobbing in her floatsuit but it might be an issue for smaller kids. There was a kid's themed park almost next door "The Land of Jan Klassen" with lots of things to play on for under-8s or was it under-10s, but most of the other places we visited involved us going north to Arnhem first !
We enjoyed both holidays and may well go back to Het Vennenbos in the next few years.
We spent a week last October at De Kempervennen, a CenterParcs in Holland. In comparison, CenterParcs provided much more info in English that the other places did. (That may have changed now, of course.)
Note that I booked with Landal online for Het Vennenbos and had problems paying. They did not accept credit card payments at that time, but there was no mention of that during the booking process. They sent me an invoice eventually (the first got lost in the post) which I had to pay by International Bank Transfer, costing about £35 at the time! I would advise that you check before booking directly.