Is the surprising quality the cheezy top made of thin stamped metal? Or the goofy logos? Or the cheap imitation vulcanite body?
How is the Yashica lens remarkable? Because it's a lens? I'm sorry, but you could say the same things about an Argus C-3 brick or a Petri 7S. They where cheap cameras with a surprising level of quality and a remarkable lens. But that doesn't mean they're half as good as a Canon P, A Voigtlander Vitessa, Nicca 5L, or any Leica. Those have quality and great lenses. The Yashica has an OK lens and OK quality. So their prices are just OK.
The top and bottom covers of the Yashica are made from stamped brass, just like the Leica M, the body is cast from aluminum, again, just like Leica. What is "genuine" vulcanite? The funny smelling rubber type stuff which keeps chipping and falling off my Leica M and Barnack cameras? The "vulcanite" covering used on Yashicas is much more durable than the stuff which Leica uses.
Other makers like Canon and Konica made similar cameras, but Yashica used better glass and coatings than Canon. About half the QL17 cameras I come across have lenses which are too deteriorated to save, this is almost unheard of with Yashica glass. The Canonet also frequently suffers from galvanic deterioration due to it's mix of materials and wide seals. The later Konica cameras were made of cheap stamped aluminum, and though the glass is very good, the metering system is not reliable.
There is a man here in Tokyo who modifies Yashinon 45/1.7 lenses into the Leica M mount. He is quite backlogged with orders, and his asking price for these lenses rivals later used 50mm Summicrons. I have one on order myself, and I am curious to see how well it will work with my M cameras.
The Cintar lens in the Argus cameras is mediocre at best, Yashica has never produced a lens as poor as the Cintar in any of it's models. I have come across several Petris (I have a box full of them), their build quality is not as good as the Yashicas. The Nicca 5L (I have one) uses Nikkor lenses, though ironcally enough, Nicca was taken over by Yashica, and the most advanced Nicca became the Yashca YF (which I also have) which was fitted with a Yashinon lens.
The Yashica Electro is one of the top selling rangefinder cameras of all time, so there must have been something not too bad about them. I am not a camera snob, though I have a lot of more expensive cameras, I have great fun shooting with Yashicas.