Just my two cents - I own a 90 and two 45 prisms, the PM-5 and PM-45 by far I use the PM-45 the most, I like the magnification and the way the screen looks through it. I like the relief. I find it suitable for most of the subjects I shoot, I like how easy it is to change backs and... being a wearer of glasses - sometimes I shoot with glasses sometimes without, studio shooting with/outdoor shooting without and I hate the on off on off on off glasses thing I will not do it. - Having the diopter adjustment is really nice.
RB
RB