Re: Puppy Kong? Both! I bought the puppy one's first having no idea what I needed really! When they arrived I was convinced I'd got it wrong and went out and bought the medium ones. At 8 - 10 weeks old Maisie couldn't deal with the larger size, but I now use both sizes depending on how long I need to occupy her for!
Re: Puppy Kong? Got puppy kongs. Still have one (although he has chewed the others up). Now I have 3 sizes of red ones. Find the smallest ones (same size as the puppy kong) the most useful as 2 small last longer than one medium.
Re: Puppy Kong? I just bought a small red one. Puppy teeth actually come out relatively quickly so you would only end up needing the puppy kong for a couple of weeks so financially it just wasn't worth it.