Gary, I have the Samyang 12mm and it’s not bad, but very wide so a bit of a one trick pony.
Sigma and Tokina, amongst others, have started on lenses for Fujifilm X mount now, so there is becoming more choice than OEM.
Of course, with a cheap adapter, you can use Canon EF lenses too…and others, depending on what adapter you get. For example, I use a Samyang 135mm with my FujiX which is manual focus and aperture anyhow, no loss