The newest world to open up in Disney World — Pandora: The World of Avatar — is simply stunning. I spent a good deal of time in the beautiful, immersive world, and I can't wait to go back. Every bit about Pandora is amazing, and it's worth the hype.
Avatar: Flight of Passage is an amazing 4D ride. The pre-show lasts a little longer than I'd like, though, and the pre-show seems to take up a lot of time as they "scan" guests to match with an Avatar. The ride is 4.5 minutes long, so it is a meaty ride. If you've been on Soarin', this is fairly similar. If Disney were to cut down on the pre-show, though, lines would move a lot faster.
Na'vi River Journey is a boat ride much like Small World. As you float down the Na'vi river, you'll see some beautiful scenery. It really is like being in Pandora. The music is lovely, too. The highlight of the ride is the Na'vi Shaman animatronic. She is by far the most impressive animatronic Disney has made to date, with flawless movements and beautiful detail.
Pandora's hype will likely die down by the time Galaxy's Edge opens, but the crowds weren't bad when I was there. You will have to wait in line for the rides (sometimes up to four hours), so if you're able to get fast passes, definitely grab them.