I just thought I'd share our experience on arrival yesterday.
On arrival at the Maritim we were offered an upgrade to a Prestige room as our privilege category room was not yet available. We were offered the upgrade for €30 per night. After viewing the Prestige room we turned down the offer.
After getting into our original room we felt we made the right choice. Very little difference in the rooms from what we could see although perhaps the Prestige had slightly newer furniture and fittings.
I would say though, with the prestige room you can take breakfast at La Maree beach restaurant. I am travelling with my wife and 4 year old however and the buffet breakfast suits our daughter perfectly.
Just thought I would share as I was looking for comparison on the 2 before we left in case we wanted to upgrade.