My dog loves it, the problems are maintaining it
As all the other reviews have been saying, this is a great fun toy which can keep your dog busy for ages, you can vary the challenge, and put some of your dogs regular food in to keep the number or treats down.
The disappointments came with cleaning the ball, it is really hard to clean, I tried several brushes and a special rubber gadget for cleaning awkward spaces, but nothing got all the little bits left out of the sides without using my fingernail to run down each ridge inside each gap round the outside, this would take me ages.
Also after a while I think all the play and washing may have removed a layer as it was then slightly sticky on the outside, so drying was impossible as the kitchen roll started sticking to it, and it picked up all sorts of dirt and fluff as it rolled around.
That said my golden retriever still loves it (I just hide it a lot as I can't be bothered to clean it!)