While just a photographer, and not a lens designer, I've been around long enough to notice that 'price point lenses' fall apart long before the best lenses. After all, there is a reason they hit a price point ! In the years I enjoyed toiling in a fine, professional camera shop...and hanging out in Steve Grimes' repair shop ... seeing which lenses came back in pieces, and seeing what they looked like on a repair table.... I formed my OWN opinions.
You aren't guaranteed the best lens by paying the highest price. But you are guaranteed that a bargain lens will not last as long as a fine one, and optical goodness is directly related to the mechanical construction.
My 50 year old Summicron gives great results, is tight as a drum. My 135 Sonnar is 67 years old, and gives first rate results. And looks new.
Quanteray is a 'store brand' lens, a standard, inexpensive design that can be bought in quantity to sell at high profit by the large shops able to take advantage of this.
From time to time, Vivitar made good lenses, that approached Nikon quality until the mechanics failed. Mainly, Vivitar has been a short-term bargain lens.
Compared to the generally first rate Minolta and Olympus products, there really isn't any comparison.
To survive in the market, everyone but Leica ( and Contax ) had to make a 'bargain line'. But buying a first rate lens from a cameramaker has always been the best value.
Today, when the prices for superb quality Minolta or Olympus lenses are so low, why even think about putting a second or third rate ( or worse ) lens on your camera.
Time is far more important than money. Run out of money, make somemore. Run out of time, and what ?
The OLD fashioned advice was "spend as much as you can afford on as little as you need". It is still the only way to go.
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