AdoptOpenJDK is the much larger project with broad community backing (We even have Amazon contribute) from IBM, Red Hat, Azul, Ocado, Microsoft etc. It's got a fully open and auditable build and test pipeline and supports a massive number of platforms (arm32/64, AIX, s390, Mac, Windows, Linux x86, PPC etc) and versions (8, 9, 10, 11, amber, 12 beta et al). We've already had over 2M downloads and are definitely in production in a lot of places.

We'll be working with Amazon to make sure there's some consistency between the two, no point in fragmenting.

Corretto is an obvious choice if you're an AWS user, for everything else Adopt is also a decent choice.