Wolfgang Puck Express in DTD is probably the best CS on property. The food is really TS quality. We dined there twice in June. The rotisarrie chicken w/garlic mashed potatoes is amazing!! Each time we got that and a pasta dish to share. There you're getting good quality food and a decent quantity of it.
Comic Rays is good and so is Flame Tree BBQ at AK.
In Epcot, we usually share CS meals just to experience the different cuisines. I've heard that the Tangerine Cafe in Morocco is really good and serves a large quantity of food. We also like Mexico's combination platter.