From the restaurants I've been to, hmm... I think it's a toss up between Mythos and The Three Broomstics.
I love the theming and the
experience of eating at Three Broomsticks, but the food is inconsistent, unfortunately. I love grabbing some fish and chips with a butterbeer, and a chocolate trifle for desert, and enjoying the magic and the joy of the people around me. But yeah, the food isn't always the same. The fast service is good though, and the theming can't be beat.
Mythos also has great theming, but it's... different from 3B. Three Broomsticks is just magic! Though I LOVE me some Mythos risotto! And I've also had the burgers and soup, and the food has NEVER disappointed me or anyone else I've eaten with. But you always have to wait, even with a reservation, and there are always plenty of empty tables! I don't get it... Anyways, the wait is worth it!
I think I need to check out Burger Digs again on my next visit. You guys have gotten me curious! The couple of times I've been there I just got a burger and either left or ate right there in the front. I didn't know you could eat at a terrace balcony! And Teebin, I'll try to get a pic inside the bathroom (if there's no one there). I've already done it in the Wizarding World bathrooms...