I recently watched the Making of Diagon Alley video that NBC made after hearing my boyfriend rave about it.
I would have to say that they have exceeded Disney's immersive imagineering. I think the closest thing to WWoHP that Disney has done is (maybe) that Tangled BATHROOM!
After watching the episode we are cutting our last 4 days of our trip and heading over to Universal for a 4 night stay. Oddly enough, it's way cheaper and we will be staying in the on site nicer hotels. (With tickets included its cheaper than the Beach Club resort alone for those nights WITH my 40% military discount at Disney)
That is 4 days Disney isn't getting my money. How about everyone else?
This also dropped us down from needing annual passes to only needing 10 day park hoppers! So more money saved by me and lost by Disney!