I just want to add that I am a completely satisfied Pimax customer - while it does has some issues, a modded Vive DAS and proper positioning - IPD configuration largely solved them for me. It truly is a bliss, if it wasn't for the black levels.
The fov is subjective. I still pay a couple of games on my Rift because of Touch and once in the heat of the action the binocular effect fades away. for me. However, for flightsims and racing I much rather the Pimax's fov. It has a much greater sense of speed imo. Also, picking up movement in the periphery is closer to RL
I was playing In Death on my Rift ( Vive wands won't cut it) and missed an enemy hiding in a corner right beside me. Given his proximity to me, I would have seen him in the Pimax's fov, so while my brain can ignore the sides of a smaller fov, it's can't compensate for what I cannot see.