Nikkors have better optics and far better construction than any of the aftermarket stuff.
Not speaking of a particular lens but of the lineup in general IMHO there are only a handfull of companies whose glass can even give Nikon's a decent contest:
-Leica. Great quality, insane price.
-Contax/Zeiss. Great quality. Not insanely priced...but in need of time on the couch.
Canon. Pretty close in quality and price.
Not meant to dog anyone's favorite but these are my honest opinions from having used and/or owned all of the above...and excluding medium format because that's a whole different world.
As far as construction...I have Nikkor lenses from the 50's which work perfectly and I have never seen one wear out.
Quantaray is made by, I think, Sigma. It isn't junk but for $50.00 it is IMHO a false savings. My only non Nikkor lenses are a Sigma 400MM F5.6 and a 16MM fisheye Zenitar (Russian duplicate of a Nikkor) and I bought them because they were a pittance of the price of a Nikkor and are lengths I almost never need/use.
These lenses are in your everyday bread and butter range however and you won't regret the Nikkor. If the $50.00 is that critical I'd buy the body only and look for a used Nikkor first.
LWW