Originally Posted by
John Kasaian
More important, will any difference between the Protar and the Tessar help or hinder your photographic vision?
Speed, coverage, sharpness (if sharpness is important) physical size, cost, coating(or at least the potentiality to minimize flare) and reliability of the shutter in any given lens are, for me, are more critical issues than the marketing hype of the design. YMMV, of course!
Aside from wanting a "back up" or say a different focal length, use what you've already got unless you've got a pressing reason for making a change.