Kong is king!
This toy is a firm favourite with my Staffy, Jody. It is made of rock-hard, smooth plastic that is very robust (as it needs to be) and all but impossible for a dog to get hold of in its jaws, ensuring it will likely last a lifetime. You may initially have to teach your dog how to use it; my Jody was already used to her similar Kong Classic so she got stuck into the Wobbler straight away. It has a large capacity so that it is possible to use it as an entire meal dispenser with dry food (size of morsels permitting).
There are some downsides. One (no fault of the product per se) is that as your dog pushes it around it can make a lot of noise banging against things and it could cause damage. If you live above anyone and have hard flooring, your neighbour may end up throwing a wobbler of his own. Also, as your dog pushes it around (feverishly) it will do so without any consideration for vases, waste bins, ironing boards, bare ankles...so be warned! Another potential problem is the size of the dispensing hole. If the treats you have are particularly small they just spill out very quickly and the fun factor or use as a feeding pacemaker is minimal. Larger treats that won't fall through the hole are even more inappropriate and what is more, this has proved to be the case with what seems to be the standard size of dry food morsel. I have had to cut treats to size or partially tape over the hole.
Unfortunately for me the Wobbler fits under my lounge coffee table and always gets stuck there with my Staffy barking for me to free it. It then makes one circuit of the room, only to wind up right back again. Notwithstanding these drawbacks my Jody definately loves the Wobbler and gets excited when she sees me pick it up. It is hilarious to watch her play with it; if she can't get a treat out of it fairly quickly she becomes frustrated and growls and barks at it. Sometimes this coincides with it dispensing a treat which makes her think the growling caused it! At other times she is so intent on driving it across the floor that she fails to see a dispensed treat and that it makes it more hilarious when she starts barking at it.