I only know from reading here a bit about them.
WPE is a counter service in Marketplace and it a great deal for the
DDP. It is a lot of tasty food and great desserts.
WPCE is the counter service that is in West Side. I believe I've read conflicting reports about whether this spot takes DDP or not. The menus are very similar.
WPC is a table service that some love and some don't. The link from the Dis says they DO NOT recommend it. Hmmm. I don't think I've read a review in a while. WPC does accept DDP.
WPUpstairs is a higher end restaurant (read expensive). I don't believe it participates in the DDP so I honestly haven't paid it too much attention.
We will be trying WPE in Marketplace. Many of the photo reviews I've read look delish and I realllllllllllly love creme brulee so I'd go even if I just ordered that.