Spoilt for choice! All these motivational dog food toys provide a different experience for your dog - it's like the difference between ludo and snakes and ladders.
With these food balls, it's best to put your dogs dry complete food in and let them roll them about to get the food treats. Use indoors and outside.
Even these toys provide a different experience. The Molecule ball produces a more random number of treats, and your dog can pick it up when it gets stuck in a corner. The Canac food ball tends to take longer to empty, just letting go of one or two pieces of food at a time.
The molecule ball is quite soft plastic and probably not the best toy if your dog is a strong chewer. NOTE: it seems that the "molecule" balls have been discountinued. At present, the large moleculeball is replaced by a similar product which has an adjustable filler hole.
The Canac food ball is made from really tough plastic, and will tend to last longer than some others.