[tptacek]

You'll have to do some legwork, because discussions of PGP on HN quickly become unproductive; PGP has a very... "engaged" user subculture.

A good Google search to start with is [matthew green PGP].

At this point, the serious discussion to have is less "what's a critical assessment of PGP" (dozens have been made over the last decade) but rather "for a given use case, what's the best alternative?"