FAA approval is basically "does no harm". Before I spent money on it, I'd want to see independent test results showing less friction, lower wear, etc. And not over 10 or 50 hours, but over the life of a variety of engines.
I use Camguard as there seems to be more history of its effectiveness although it has to be used at every oil change. Supposedly, the Microlon is a one time deal.
My oil analysis results show reduced wear after using Camguard. I'm early in the process but so far it seems worth it.