Apart from a bully stick, interactive toys that dispense treats are the most effective way to keep my 18 lb terrier mix busy and mentally occupied. We've bought several of them: The Buster Mini Cube (made of *very* hard plastic and too noisy even on a carpeted floor), StarMark Bob-A-Lot (one of the best although it's light enough for him to throw it around and make a lot of noise), and the Premier Busy Buddy Tug-A-Jug (also effective but again somewhat light and hard).
Benji has never had trouble figuring out how to play with any of these and although he destroys plush toys in a flash, he hasn't been able to do any damage to these. The problem with all three of them is that they are just too noisy for him to play with in our living room very early in the morning when we want him occupied but our neighbor in the apartment next door is sleeping.
So when I saw the Kong Wobbler online it looked like it might be the best yet. I tried to find the toy in various retail stores, but it is new, and none of them carried it. So I ordered it without knowing anything about it but a photo. I assumed it would be that hard rubber traditional Kongs are made from and that even if Benji threw it around it would be less noisy.
Upon arrival I realized the toy is nothing like what I imagined - but that's not necessarily a bad thing. First of all the thing is huge, which I couldn't tell from the photo. It is almost as tall as the Bob-A-Lot. I'm not sure a dog much smaller than Benji could manipulate it satisfactorily and Kong recommends it for medium to large dogs. It's also made of *very* hard plastic which I think a lot of dogs would find very unsatisfying to chew compared to a traditional Kong. Another drawback is that the hole the treats fall out of is way too big for kibble and unlike the Bob-A-Lot, the hole is not adjustable. I made the hole smaller with scotch tape and the toy works fine.
So why would you consider the Kong Wobbler in favor of the other toys? It's *heavy*. I mean really surprisingly heavy compared to the others. The other toys are light enough so that Benji can grasp them in his front paws and propel the toy across the room where they bang against furniture. It's fun to watch but nerve wracking. The Kong Wobbler is just too heavy for for him to "toss" (although he's giving it his best shot while I type this). So the toy rolls around on the rug rather than flying through the air.
Any of these toys would be great for a dog with a yard. For use in an apartment, I'd give the Wobbler a slight edge. It is also a little bit less expensive than the Bob-A-Lot and the Tug-A-Jug. I can't really recommend the Buster Cube for indoor use. It's like letting young kids play with a baseball in the living room