
The only time I, sort-of, used a pet Courier Service was when we moved from the East down here in the SW. We bought 3 with us and with a loaded car etc. and not feeling up to doing the entire trip in one day (we stopped off overnight and I later discovered I had walking pneumonia) we had this Service pick up our 3, keep them overnight and deliver them to our new home the next day. I wasn't terribly happy about doing that and for sure, the one of the 3 I thought would take it in her stride, wasn't really the same again, with strange people. They were however, all adults.
I'd never do that to a puppy I'd bred and in fact flew with one I sold to Geneva. On the other hand, when I bought our foundation bitch, and then a male, they came from the UK to Canada via a Courier at the UK end. I picked them up myself at Toronto International.
If you are buying this puppy, go collect it yourself. You should always meet the breeder face to face, see how they raise their puppies, mum etc. When I bought my two, I knew, personally, the breeder of each and what I was buying (bloodlines) plus I trusted them not to send me 'a dud'.

If this is you sending a puppy off, then I'd prefer to have the new people come collect him, or take him to the new home myself.