Having returned from a week at La Vallee, I've mixed opinions on Keycamp.  Both Keycamp and Eurocamp have various flavours of accommodation at La Vallee - I stayed in a Grand 29 3 bed. 

Before getting to La Vallee, be aware that the directions Keycamp provide expect you to arrive from the south, near the A13.

On arriving at La Vallee you need to make your way to the Keycamp office where a staff member will show you to your accommodation.  From the outset the staff are obviously students - 18-21yrs old.  Over the course of a week its clear that Keycamp La Vallee is run by Keycamp students.  I've nothing against students, I was one once :)  However, if Keycamp trained and paid them a little more, and invested a little more in the accommodation, I would have been a lot happier.  Take for example the accommodation;  surely Keycamp could have provide mattress covers so its customers didn't have to look at the disgusting mattress prior to making your own beds? You can't tell me that accidents didn't happen on the mattresses by its younger customers!  Next the cleanliest of the accommodation itself.  If Keycamp provided suitable training, then the Microwave might have been cleaned prior to our arrival.  The sofa could probably do with a clean once a year as well. 

As to the campsite itself, the playground weren't bad, the probably again however was with Keycamp's "Fun Station" - in the case of La Vallee, staffed by two students who couldn't motivate the dead, let alone a 3yr old.  Overall the Fun Station was more of a student Sun Bathing Station.

As to the onsite pools, even though they're supposedly heated to 26C, they still felt cold, and you need Speedos if you're a male - not shorts allowed - shame Keycamp didn't tell you this before you packed.

In summary, given the above I actually had a good week at La Vallee, even though the weather was appalling. This was mainly due to being with the family, away from work, nowhere near a computer, and without a cell phone and blackberry buzzing every few minutes throughout the day :)  Would I use Keycamp again?  Possibly, but I'd probably go further south in France in an attempt to get better weather :)