I recently started using it based on comments here and it's been great personally. The few times it hasn't gone through, I've reached out and they have resolved it quickly but I do take screenshots as recommended. Even with screenshots and all that, it's pretty quick and not much of a hassle IMO. Granted now that I say that, I'll probably have issues...
Also, what I've noticed is when they have specific cashback for certain items, it stacks on top of the 1%-5% (or more) for the specific site, which is nice. The thing you have to be careful off is if you use other cashback applications, if you have something else active then Honey won't work and vice-versa. It would be double dipping basically. I learnt that the hard way the first time I used Honey (since I'm relatively new to these apps) but Honey CS actually worked with me and still gave me some cash back which they didn't have to.
WRT Honey 20% at Disney, I'm only seeing up to 9% myself unfortunately so looks like mileage does vary...