This was a quandry I had with Harvey.
I bypassed the puppy kong and bought a small adult kong (the red ones) and a large one (the red rubber seems to be tougher than the puppy blue kongs) - I used to fill the small one with kibble and top it off with peanut butter - the larger one I'd fill with carrots and chopped up hotdogs - fill it with a natural bouillion and freeze it (remember to plug the small hole in the kong first, with something like cream cheese or peanut butter - otherwise the bouillion just pours out!!) These two used to keep Harvey happy for a couple of hours whilst I was out - now he just sleeps while I'm away!! I have two of each size so I can rotate them - one in the freezer while one being used...
....kongs are also great to put in their food bowl if your pup has a tendency to hoover their food!! Just place the kong in the food - because the Kong restricts the space available for pup to yomp at the food, it slows down the eating process - it's worked so well with Harvey that we don't need to use one now - he just takes his time!
The treat balls are great - but as another COLer pointed out to me - there are small parts in that - as well as dips and grooves where pups teeth can get caught - so I never leave him unattended with the treat ball.
