Dang, this is a hard one. There are so many considerations:
- General utility (size, weight, handling, focal length)
- Optical quality (sharpness, bokeh)
- Build
- Pixy dust quotient
- Results
Optical quality and build would be in favor of the FA 77/1.8 Limited or any number of my fast 50s. General utility highly favors the FA 35/2. It helps that it is no optical slouch either and is made pretty well too. The FA 77 fairly wallows in pixie dust, but then so does my KMZ Helios 44M 58/2. In terms of "keepers", the rewards go to the the FA 35/2, KMZ MC Zenitar 16/2.8 Fisheye, and Helios 44M 58/2.
Hmmmmm...choosing is so hard. I think that I will simply go with the prime that spent the most time on my cameras since 2007...
Pentax-FA 35/2
The FA 77/1.8 is exceptional in every way, but the focal length is clumsy in general use. Some of my best work has been done with the Helios 44M, but it is clumsy to use on a K-mount camera. The FA 35/2 wins by default of being in the 85th %-tile in all categories
Steve
(...I am so blessed with primes...)