1. I'm not a huge fan of Winnie the Pooh. The story has always just been meh to me. Also, rides that follow the story of a movie prior always seem rushed. They are usually missing something that makes it feel complete.
2. Mystic Manor is a new narrative created just for the ride. I like the idea of magic in an attraction as unexplainable things can happen without reason. The visual effects in Mystic Manor are also extremely impressive. I love the final room with the monkey statue and vortex.
I do think that Pooh's Honey Hunt uses the trackless system better. In mystic manor there may be variations in the track, but each car sees the same thing. And most of the ride the cars move in the same sequence like an omnimover or classic tracked dark ride. So if I was voting for better use of the trackless system, it would be Pooh's Honey Hunt. But since it is simply better dark ride, Mystic Manor had to win. Plus being a newer ride gives it slightly more appeal. If both rides were introduced at the same time, maybe my opinion would differ.
The monkey is definitely cute, but Pooh has a long history and is pretty darn adorable himself. What else would you expect from Disney?
I'd love to ride both rides, but voted for Mystic Manor.