its not any better than any of the good ones out there, it is built to spec, finish is great, it does look a little chunky, might be a schmudge heavier than a colt, thats about it.
What makes an AR shoot accurately are the barrel, chamber and bolt lock up.
Reliability in Cycling is gas block, tube, bolt, buffer and spring
As long as the upper and lower are built to spec, using quality material, manufacturing and inspection processes, and fit together you are good to go
That being said there is a difference between an nea upper and a vltor upper, whoever says different, pffft dream on...
If you dont care, well buy an nea upper, or a christensen arms upper, dont forget to also shop for a good plastic surgeon for when the upper explodes in your face