Mike Wuerthele, AppleInsider:

Noted Apple analyst Ming-Chi Kuo has weighed in on early sales of Apple’s new products, and is seeing massive demand for the iPhone XS Max over the iPhone XS, with Apple Watch Series 4 demand so high that supply constraints may extend unless Apple brings on more assemblers.

And:

In a note seen by AppleInsider TF Securities’ Ming-Chi Kuo is seeing between three and four times the demand for the iPhone XS Max versus the iPhone XS.

And:

Worldwide, the 256GB model of the iPhone XS Max is reportedly most popular, with the 512GB one suffering from a “serious shortage” because of low NAND flash supply.

And:

As a result of channel checks, Kuo is expecting about 19.5 million Apple Watches shipped before the end of the year, up from 18 million.

Astonishing sales. Apple has this down to a science.