I feel that it partly depends on what you are willing to pay and what kind of experiences/ambiance we're talking about.
BOG is pretty good food-wise but has little ambiance beyond the sheer dedication to decor they've invested. I loved that movie growing up, so I always feel like I'm actually in it when I go and I'm very happy. But it's often crowded and there is nothing else going on save you staring at pretty things. The West Wing has the best ambiance IMO.
Ohana is my favorite breakfast place, if you can get in. Lilo and Stitch are great. When the Poly isn't under construction, the views are also fun. They play music and there is a little parade that, even if you don't participate, can be fun to watch. I always have a good time there, and everyone introduces themselves as cousin and says aloha. The kitchen is small though, as it only operates partially for breakfast, so if you want extra of something ask well in advance. I drag everyone new here and they've all loved it. I'm also a huge Pluto and Stitch fan, and they've almost always played nicely with me.
50s Prime Time is an experience. Hopefully you get someone who is really into it. The idea is that they're all family members and you are kind of their house guests. Food can take a while to get to your table, and it's all stuff people might make at home (I mean, not me because I can't cook. But other people maybe). Lasagna, meatloaf, friend chicken, etc. I, personally, like being sassed by the waitstaff, which is supposed to be part of the job. I've been praised for finishing what was on my plate, chastised for having elbows on the table; my friend was nicknamed Rusty (he's a redhead) and told to set the table, then he was yelled at for not doing it right. It's all in character and we ended up cracking a lot of jokes and "telling on" each other. I like the atmosphere as well. One of my favorite Hollywood Studios locations, tbh.
Not really a sit-down, but the new Trader Sam's Grog Grotto at the Polynesian Resort is pretty kickin. I was there for the opening and had a blast. It might be packed, but the outdoor area is nice provided the weather cooperates. They have appetizers and non-alcoholic drinks. It comes off as festive and fun, kind of like a tropical backyard bbq as opposed to a luau (no open fires or dancers here). Your kids won't be able to go into the main bar area, but cool things happen if you manage to get in.
Hoop de Hoo and Spirit of Aloha are dinner/show combos. If you want one of those, I've always heard glowing things about Hoop de Hoo and more mixed results on Spirit of Aloha.
Decent burgers and shakes. We usually have a lunch here each trip.
