The Harry Potter restaurants are more about the ambiance than the food. It is definitely quick-service food. DH loves their fish & chips. I loved the Ploughman's Platter (both at US - Leaky Cauldron) BTW, the Ploughman's Platter is different kinds of cheeses, breads, and an apple beet salad (which I get every time I'm at Universal...I'm a little -a lot- obsessed with beets.)
The rib platter was pretty good at Thunder Falls, might even be the same ribs they sell at the Three Broomsticks (I find ribs to be too rich for my stomach, even though they are tasty! So, I don't get them often.) But, Thunder Falls does have a nice smoked turkey leg platter.
Both places are quick service, and pretty good for what they are.
I won't answer your question about the Pad Thai, as I did not care for the service or my cold food when we went to Mythos, so we haven't gone back. BUT, I am in the minority, as most people love Mythos.