I like the plane skins but then they go with the name of my town. Not fond of the faster turnaround time on planes. I agree that 2X rewards would have been better for it.
I do like the dairy reduction because it seems like I'm always needing those products and am constantly making them. Even though I try to keep some in the barn I go through them so fast then I tend to need more of cream, cheese and butter all at the same time! With this and the expanded barn I can increased my inventory.
Coins, TC and expansions are always welcome. Since I've always struggled getting clovers for HOL daily tasks, I'm hoarding any I get from Double Luck.
I think there have been dud rewards in all 3 of the experiments but IMO the good has outweighed the bad.