I was there on Sunday. Park open was slated for 8 am. We showed up at 6:50 am, as we had heard that the park opened 45 minutes early on Saturday. When we walked up to the gate, we learned that the park had opened at 6:45, or 1:15 early. We went in and went straight to Flight of Passage. My soon wasn't tall enough to ride, so we did parent swap. My family walked straight through the queue, with no stopping, and from the time they went in the entrance till they came out, it took 55 minutes. The queue is apparently the longest queue of any ride in the world. They said it was beautifully themed, but I have also heard that if the line backs up to the beginning and is doing the normal crawl, it is a 5 hour wait.
After they got off Flight of Passage, we went to the Na'vi River Journey (at this point it was 8:15 am), but the wait was already 120 minutes and we didn't feel like standing in line. Used the fast pass from parent swap for Flight of Passage and left the land.
I walked around the merchandise some while waiting for family to get off the ride, it was pretty neat. The banshee adoption is one of those toys that people are going to throw money at. It looked pretty neat. By the time my family went to look in the shop, there was a line with a 30 minute wait just to get in.
After riding Flight of Passage, we went to ride Safari. As we walked that way, the line for Flight of Passage stretched to within 100 feet of the Lion King show area. They had it listed as a 295 minute wait, but a friend of my sister (she used to work there) who was working the land told her it was more like a 500 minute wait.
Unlike, PH's experience, it did not clear out in the middle of the day that day. We kept checking the wait time for the rides on the Disney app. Saw the river ride get up to 195 minutes and the Flight of Passage reach 395.
The immersion of the land is fantastic. You can't hear any other noise from the rest of AK. You feel like you are in another land. The level of immersion in this land, gets me really excited about Star Wars Land, as there is little doubt they will step up the immersive feel there. I have heard the are things in the land that will actually remember you over time and interact with you accordingly.