So, we went for the first time this past week. Overall, pretty good experience. I'd say I was by far we were most impressed with How to Train Your Dragon land. I honestly have not seen the movies, so low expectations may be part of it, but it felt great. The area had nice flow, and most importantly, there was a TON to do. 3 rides, a show (which was outstanding), and a playground on top of meet and greets. Close second for us was Dark Universe. It really had a cool theme and vibe, and Monsters Unchained was every bit as impressive as people made it out to be.
Downsides, Super Nintendo is just not well done for us. My teenager thought the theming was if a Nintendo threw up all the games in it's memory. Not nearly enough space to walk, and it didn't feel cohesive. DK ride was fun, but I get the complaints about Mario Kart. I can say most of us left that ride frustrated that we couldn't get things to work like we wanted. Yoshi ride feels like it needs to be a bit longer with no lap bars (just put in doors like people mover). That said, we all enjoyed Toadstool Cafe (albeit found it a bit creepy seeing all the items with mushrooms), and the Donkey Kong area does have really cool theming (especially at night). But we left that with a feeling of what could have been.
The Harry Potter land we all agreed was our least favorite. Things were tight, and there just wasn't a ton to do. The show never opened when we were there, so legit there was just a single ride which everyone agree was good, but not nearly worth the 2 hour wait.
Overall, we had a good time, and it is very beautiful, but it does feel like 3 of the 4 portal areas need at least 2-3 or more things to make them full. I would go back if we are back at Universal, but no way I would buy a single ticket for it.