Originally Posted by
beachmouse
Mercure is easy- it's the dumping ground for full service properties that don't really fit to any other specific Accor brand standard- you might get a nice country manor complex or a ski hotel or a concrete bunker just off the motorway. So Doubletree without the cookie baker. Novotel is the modern IKEA theme with better food options than an Ibis Style
DoubleTree isn't necessarily meant to be full service, I don't think. Often it is, but it's also where Hilton dumps smaller properties that aren't big enough / full service enough to be a proper Hilton. In Europe at least, DoubleTrees will often be smaller and missing facilities such as 24 hour room service and a decent business centre that you can take for granted at a Hilton.
Even having said that, there are some excellent DoubleTrees (DoubleTree Doha Old Town comes to mind, if that was branded a Conrad instead it would still be considered one of the best Conrads). Crowne Plaza I struggle to name hotels that come quite up to that standard (I really like CP Causeway Bay, but even then it's not quite up to the same standard as the best DoubleTrees).