I've been to both, and prefer WPE to the WPC. You have to realize you are comparing a QS restuarant to a TS restaurant. Lots of folks on the DIS have said they liked WPC, but we found it overpriced, and the food just so-so.
The atmosphere and decor of the cafe are cool. We really like the open kitchens at both. I probably would have enjoyed a table with a view of the chefs at the Cafe. I should also mention that we didn't try any of the desserts, though they looked really good. Also, part of our problem was a sub-par waitress. Among her numerous faluts, forgetting some of our food and bread. So maybe better service would have swayed my impressions more favorably. All the tables around us had bread, and it's not like we didn't order entrees (As in I wouldn't expect bread if we had ordered pizza.) As for the food, the sushi wasn't bad, but the kid's pizza was a joke. I think I also ordered ravioli and found the portion very skimpy - not enough to fill me by far.
Now compare that to the Express, where the portions are quite good for the price. For a QS, the options are diverse. They have yummy pizza with unusual toppings, and other creative menu items. Last time I was there, they had homemade potato chips. They wern't the best thing I've ever tasted, but it was kind of an unusual thing for a QS place. The pasta has also been good there, and they use high quality ingredients -like good bacon. The kids' portions were good. I also like outdoor tables. But it is disposible plates and silverware.
We haven't eaten at too many other places at DTD. When we go, the WPE is our favorite place to go, and it's inexpensive. Of the places we've tried though, HoB was pretty good. It's a certain type of food, so you have to all be in the mood for that type of food, but it was good the last time we went. (2005)