Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
Ubuntu Touch has been pretty decent, and because of how it's built, device support is a lot more widespread. Although it's in this perpetually broken state now, because of the transition to the Focal base.
No luck at all with Postmarket though, on any of my devices. One is marked as bootable but unusable, but I can't even install it fully
Ahh, my appraisal might be the opposite, PMOS seemed to have better software and support for things like the Pinephone and I thought it ran on more devices, but I am happy to see both projects and it's nice to see both designs
On a device that supports PM, it will without a doubt have better software support. Current UbPorts runs on Ubuntu 16.04 base, so it basically can't run anything new until they fully migrate to at least 20.04