To me, the NF Comp is the best glass available at any price for a scope intended for our sport. I also like that they are an American company and have a great warranty. Although, I think problems with them are extremely rare, I don't doubt that you could have a defect or issue with them, just as with any make, model or price scope or product in general.
I will also say that perceived differences in "cutting through" mirage is just that..perception. Just as turning the power down will make mirage less noticeable, it doesn't mean it's not there...just that you don't see it. I believe that the better glass simply sees mirage that lesser glass does not. JMHO.
The reason the NF Comp has such good glass is because it uses ED glass. Because they do call it ED glass, I believe they get at least that glass from Nikon, because ED and Super-ED glass are Nikon products, something they developed for their camera lenses in the 1970s.
ED glass has been introduced to riflescopes in the last few years. It has also been introduced to spotting scopes, even before riflescopes because birders. These folk love their ED or fluorite glass in their scopes. Fluorite glass is currently the best for eliminating chromatic aberration, but it's fragile and very expensive. The ED glass developed by Nikon goes a long way to eliminate CA, and it's a lot sturdier than fluorite and, while more expensive than regular optical glass, it's not as expensive as fluorite glass.
If this was the first riflescope you got with ED glass, I totally get your opening statement. My March-X 5-50X56 also has ED glass, (probably Nikon's for the reason stated earlier) and comparing to my Nightforce NXS 12-42x56 just makes the latter pale in comparison. I wrote a fairly long post here over a year ago comparing the Comp to the March-X and the reasons why I went with the March-X. I like its 13% larger objective and its 10 yards (vs 25 yard) focusing range.
The March-X High Master series mentioned in another thread uses Super-ED glass, another Nikon product. This gets it even closer to fluorite glass "perfection."
It has been my observation that mirage is being tamed by ED glass, to the point where I discern it but it is not affecting the target the way non-ED glass show it to my eye. Also, mirage is a function of depth of field. The greater the depth of field, the more mirage you will discern. Depth of field is a function of magnification, distance and aperture. The larger objective lens of the March-X (56mm VS 52mm on the Comp), will reduce the depth of field. I also believe that the March-X has larger internal lenses in its 34mm tube with a still-constrained 60MOA total adjustment range. That probably increases the aperture and thus further reduces the depth of field.
That said, I see mirage in my 82mm Kowa without ED lenses, that I do not see in my March-X. Of course, the two optics are focused at different distances, but the images are dramatically different to my eye in heavy mirage days, which is pretty much every match at Bayou, except when the wind is above 15MPH or there's actual frost on the ground. Even that last one does not last much past the first few hours of direct sunlight.
ETA: I also take note of some devices sold by some riflescope manufacturers that partially hide the objective lens. This has the effect of reducing the aperture, increasing the f-number and extending the depth of field, and thus show even more mirage. I noticed the same thing using a medium yellow filter on my NXS, which had the effect of increasing the f-number by 2/3 stops and showed we the mirage more distinctly.
Mirage is due to sunlight going through water vapor and hot air vs colder air, refraction, different wavelengths, etc. It is my belief (a hypothesis, really) that this increases the color fringing and the ED glass reduces or eliminates this somewhat and thus tames it. One day, when I get really smart and have some time to spend doing this, I will put the hypothesis on paper with calculation to either confirm or infirm said hypothesis. For now, all I have are data points collected from empirical tests.