After trying perhaps 20-25 6x6 folders, two come through as outstanding, not just for the lens quality but also usable features.
First choice: Mamiya Six Automat: film plane very flat, superb well coated lens, unique focus method, built like a tank, fine shutter with 1/500th, coupled rangefinder, shutter cocks as film advances (saves time), bright finder window, double exposure prevention.
Second choice: Iskra. I know people have problems with them but its because they bought a worn out camera. Mine was nearly mint and has performed flawlessly for a decade or more. Very good lens, fine shutter with 1/500th, double exposure interlock, automatically senses beginning of film so no arrows to line up, automatically resets film counter, handles well, looks great, *has generous lugs for carrying straps* (a rarity in MF folders, so you don't need a half case), good viewfinder window, coupled rangefinder, auto stop when winding film.
If you want ease & speed, no red windows but some sort of auto advance like these two cameras. Auto shutter cocking (Mamiya) makes them a lot easier to use with gloves. Double exposure prevention keeps you from finding that shot-of-a-lifetime was double exposed. Unlike some uncoated lenses, or poor single coats, you do not have to use a lens hood although in some circumstances it may behoove you to. Filters not hard to find for the Mamiya, more difficult for the Iskra but there are work-arounds. My repairman, Bill Moritz at Pro Camera in Charlottesville, says they are both easy to repair; he has CLAd both shutters and adjusted rangefinders.