Condition of the sample you find is probably more important than any differences among the Pen F models. I have two FT and one FV and was a bit surprised that this FV's viewfinder isn't any brighter than the others. May need cleaning... These are old cameras from the 1960s so I would say just go with the best sample you find. The FT runs fine without batteries, and FWIW the FT metering is kinda weird anyway!
The double-stroke film advance is easy to get used to, and is a smart design decision... because there is right-angle gearing in there to cock the rotating shutter. The wind lever's shaft is vertical while the shutter rotates on a horizontal axis. This gearing tends to be a bit delicate I understand, and is prone to feeling pretty rough. Be gentle!