They are very common here in Austin. The woman working at the counter in the Post Office wears one and the last couple of doctors I've visited wear them. How common are they? I'm not sure. The fact that they have a distinctive appearance makes them much easier to identify than other watches since the other watch companies make so many models.

It would be interesting to see the geographic distribution; I was in Delaware a two years ago and used mine to pay for my purchases at a Bookstore and everyone was quite surprised--they were unaware of the active Apple Pay feature on their own point of sales terminals.