The other popular lens that were bundled with them were actually considered better than the Schneider Xenar back in the day - the Kodak Ektar had the best reputation, the Optar was no slouch at all. For all practical purposes they are the same quality, so you'd want to get one in the nicest shape and with a properly working shutter. Chances are that any shutter that has been sitting in an attic for 40-plus years is gummy and any rangefinder will be dirty, so getting things cleaned up and running right could cost as much as the camera. That's why it is usually best to buy the prettiest one even if you don't care about cosmetics (it may well be gummed up too but it takes less to get it running again). I guess the absolute best one to buy is one from another photographer who was using it (and is honest, haha).