The Cube definitely makes your dog work harder, even I struggle to get all the food out. Unfortunately even with the mini cube, my baby yorkie struggles to rotate the cube (maybe its the hard flooring make it more difficult to rotate?). I agree with the other reviewer, I also found the centre section of the cube very difficult to pull out. I managed to open twice however have not managed to open it since... : ( You can only run water through the center section to clean and don't think you can pull the cube apart unless you break the cube. I don't like the idea that I can't get the cube properly cleaned if I were a regular user.
Probably the best £10 I've ever spent, keeps my dog busy for at least half an hour when filled with food. The helper-skelter mechanism means the food comes out more randomly than other treat toys and makes the dog work harder. You can also adjust the difficulty by twisting the centre piece. I had a real struggle at first to get the centre section out for filling and cleaning, but it loosened up over time and is now easy to remove. A word of warning, it can be very noisy especially on hard floors, but it's still second-to-none at keeping the dog occupied!