My Father was an Exakta/Exa user in the 1950s/60's. I remember him saying that they were fine cameras, but spoiled by Quality Control issues on the later models....shutter faults, lens with poor definition, etc.
Maybe like a lot of the Eastern bloc products from that time...good simple design, rock solid build, but perhaps made by a workforce and sold by a marketing dept that had little real interest in their products.
But good examples seem to have lasted well are still very usable and collectable.