Sorry if it is a little late, but I got to experience the ride last Thursday, and so I thought I'd put in my two cents. This will be quite long, but the TL;DR version is that I will echo what most reviewers have already said, in basically all cases.
First, a little background about me as a reviewer. I grew up attending Six Flags Over Texas, so with the exception of Yosemite Sam and the Gold River Adventure, I grew up not really knowing what a dark ride was (those of you who know the ride know that there isn't much special about it, although it has its charms). My first visit to WDW was not until I was 21 years old, and I was absolutely blown away. I ran around and danced and sang like a 6 year old child. I just didn't know that theming like that, that amount of detail and loving care was possible. Now, with last weekend being my first visit to UOR, I was blown away yet again. I'd be lying if I said that I hadn't drunk a little of the Disney Kool-Aid, and was under the impression that Universal was not as devoted, not as detailed or as amazing. I am happy to say how wrong I was. I'm still a Disney guy, but I love Universal now too!
So, Reign of Kong. My traveling companions and I had dedicated our first day entirely to the Wizarding World, but I had hyped up this attraction to them so much that we decided to break our immersion just for a little while and experience Kong. We got in line before the technical rehearsal began (at about 5:45), and to make a long story short, we ended up waiting close to three hours, I think, thanks to the length of the queue and the extended delay that occurred. My party is all of the consensus that it was worth the wait.
Everything in the queue was functional for us, although there were no scare actors. That was a little sad for me, but even without them that hallways is extremely foreboding - so cramped and uncomfortable, in the best way! I almost could have been convinced that the witch was a scare actor, she is amazingly real. I do feel that the story presented through the queue is engaging, despite being disjointed. Why are we outside the temple, apparently at a base-camp, then encountering the natives on their own turf, and then getting to another base camp inside their temple? Still, this didn't bother me enough to break my immersion at the time. The only queues I would rate higher are Forbidden Journey and Gringotts.
Finally, the ride itself. We sat all on the right side of row 12, which was mostly fantastic, although you can see some edges of screens and experience other breaks in immersion from this far back. Everything in the ride was functioning except for the transition screen from the 360 room to the big man himself. We found all of the 4D effects to be extremely, well, "effective"! The smells in particular were almost too real. One of my favorite effects, actually, was the illusion that the truck was speeding through the jungle when it was actually only going like 2 MPH through the 360 room, LOL! The motion all synced up beautifully and I couldn't have asked for a more real experience. Our driver was the native girl (whose name I have forgotten), who was fine, but nothing special to me. A bit cliche and perhaps even offensive, although I wouldn't know. I'd be most interested in hearing Will Denham, but I was not displeased with the native girl.
Story wise, the only thing I did not like, as many others have pointed out, is the dropping of Kate's involvement. She absolutely needed to be in the 360 scene, and I can't understand why they would not have placed her in it. Again, as many have said, that Kong and the blonde girl do not meet is almost criminal. But with the exception of that, I did not have any problem with the rapid-fire changes in location, that more or less worked for me, although it does make the pacing of the ride feel much faster than it actually is, as many have pointed out.
Kong himself is by far the most advanced AA I have ever seen (although remember I have only been to SFOT, WDW, and now UOR), and even though I had watched the Inside the Magic video before hand, there was nothing like experiencing him in person. He is so incredibly lifelike, and actually very scary in my opinion. Many reviewers seem to feel that there was only a "friend" aspect to his appearance, and no "foe", but I absolutely felt that we were creeping past him for a reason! I felt he wanted us to back away slowly before he did to us what he did to those dinosaurs!
And now, a ranking of my favorite ride-based attractions. This is in no way subjective, and is a ranking of rides only based mostly on the level of immersion, the overall experience (queue and other elements included) that I felt the most impressive to me. I did get to experience all but a few smaller rides at the resort during my time there.
1. Forbidden Journey (if this could take all five places, it would!)
2. Gringotts
3. Kong
4. Spiderman
5. Transformers
If anyone happens to have any questions or comments about my experience, please feel free to let me know!