I have only one 75, the CV 75/1.8 Heliar, and it's a good lens, and I like the results, but it's large. Somehow, I've ended up with 3 90's, a 1951 9cm/4 Elmar in LTM, a 1973 90/2.8 Tele-Elmarit M "Fat" and a c. 1970 90/2 Summicron that I got for a good price because it's cosmetically pretty ugly (but the glass, aperture and focusing are fine). I prefer the 90/2.8 for general use, got the 90/4 for use with the visoflex and bellows, then found the 90/2 at a good price, which I can also use on the visoflex and bellows, making the old Elmar just something to play with when I want an old lens look. The Summicron is hard to focus but very nice and anything that is in focus is good and sharp when wide open, but it is also very large.