So I've used FreeBSD as a desktop for a very long time. I don't think it's acceptable desktop OS by today's standards at all:

- graphics card drivers years behind (actually what made me switch to linux)

- A lot of linux graphic environment tied itself to systemd and it's friends

- Specifically, firefox lacks some features that available on Linux, Windows and macOS (related to memory consumptions and overall snappiness)

- Many things depend on FreeBSD specific patches to work and if you aren't a seasoned porter, good luck porting it yourself[1]

[1]: this one obviously depends on what kind of software you require. For it me it's a miss.