The QS fried green tomato sandwich at Fairfax Fare at HS is very tasty, and that QS place in Morocco has great falafel and babaganoush. Also at Epcot there's a food stand where you can get grilled cheese and tomato soup that's pretty tasty (I don't remember what it's called). The flatbread pizza at Pinocchio Haus is ok. For AK QS there's always Pizzafari, but I prefer just getting fries at Restaurantosaurus and loading them up with goodies from the toppings bar. I think MK is the worst for vegetarian options, especially QS.
There are definitely a lot more great choices for table service. Boma is awesome, Tusker House to me is a not quite as good version of Boma (but still great, and in the park, with characters), Biergarten has a lot of delicious vegetarian options.