Just got my copy and managed to play through it once. I played a 2 player game using this expansion and the Asia expansion as that's what we had available. I really liked the addition of the hummingbirds which give you a benefit almost every turn.
The artwork is beautiful, as usual, and the new bird cards were a nice addition with new powers. I found the game length was increased as there's another element to consider when taking your turn but didn't feel like it dragged the game out. That might change at a higher player count. However, I found the game went smoothly and added extra benefits on my your turn, at the end, it felt like I was able to accomplish more between my player mat and the hummingbird board.
Of all the expansions, this one affects the game play of Wingspan the most. If you like Wingspan, you'll probably like this expansion as it adds an additional dimension to the beloved base game.