We've done loads of Eurocamp holidays. Also Al Fresco and Canvas. They all have units on the major campsites.
We've also stayed at some of the Les Castels sites which are a little smaller. Some of them have a larger eco-focus rather than fast and furious fun.
We like the freedom, the convenience of having an on-site supermarket (often quite small and expensive), the facilities such as pool, kids clubs, restaurants etc. DD loves being able to take her bike and explore (she's 14, so we're comfortable with her going for short rides out of sight).
I wish there was some sort of halfway house such as b&b, all inclusive etc. I'd love a little bit of time off from organising breakfast every day!
We tend to go to places that are either within walking distance of a nice town, or a beach.
I echo PP who recommended going for best accom you can afford. And if you can, get the beds made up for you before you arrive (I'd happily pay someone £1,000, 000 to do this for me - it's the worst job in the world).
You can fly, fly-drive or ferry-drive. You can generally use Tesco points to pay for ferry/tunnel. If you drive, you many need to stop overnight en route. Euro amp can suggest places or MN will always have ideas.