I shot the F3 HP as my main camera for 15 years.The thing I liked the MOST about the HP finder (High Eyepoint) version is that it was/is the absolute best viewfinder ever made for eyeglass wearers...it allows you to see the ENTIRE picture area, extremely easily, due to the extended eyepoint distance, which means that you can see the entire viewfinder area with the eye as far as one inch behind the eyepiece. That alone ALWAYS made the F3 HP my preferred camera over the smaller, lighter, cheaper Nikons of the era, the FM and FE series models (which I also own). The F3 HP offers 100% viewfinder image as well as the extended eyepoint.
For me, the viewfinder of an SLR has always,always, always been one of the top two criteria I use in measuring how much I like the camera. I want to be able to SEE and frame what I am shooting with the highest degree of transparency possible, and that is an area where the F3 HP was the leader.