I have both a 3.5 tessar rollie, and a 2.8 planar role. The planar has a 3d effect I dont see with the tessar, and is sharper. I prefer the planar, but that said, there is nothing wrong with a good quality tessar design. I have a super ikonta with a 2.8 tessar that is one of the sharper lenses i own, sharper i think than my tessar rollei. I shoot a tessar design lens on my 4x5. I think that when dealing with old lenses, especially at this age, sample variation is going to be huge, and i would buy whichever one I could get that was in the best possible shape. A good tessar will likely be a better shooter than a banged up planar. Either one will make great images.