If you already have it, use it, with a Tessar you can not fail, but be gentle because, as NickT said, it is complex and the chances of repairing it are minimal. If you do not have it and planing to get one, I will not recommend it because it is uncomfortable to handle, all the controls are in a strange position and you will get into a specific lens mount system. More a collector's item than an a practical and usable camera.
I have the Super BC with the 35mm and 115mm lenses too, everything works OK, it is a beauty as Stephen said and got nice results with it, but if I could go back in time with what I know now, I would not buy it.