Im about to use one for my new EVGA HAdron build. Some things I can say about it from reviewers, and install videos are this.
The Hyper n520 is a nice looking heatsink. I love that you guys used a metal shroud to make the HS more aesthetically pleasing and more modder friendly. I like how the 92mm fans are offset to allow more clearance. I also like that this has has two 92mm fans
However, I dont like the fact that the fans are not pwm, a tad loud, don't blow too much CFM and create mediocre static pressure. The mounting system is outdated as it requires you to remove the motherboard just to remove it or install it (If your case doesn't have a cpu bracket hole this is a tremendous PITA. )
So to improve your cooler here is my recommendation.
Make you cooler lower than 140mm as it stands at 141mm and is perhaps the tallest 92mm cpu cooler out now. The Noctua NH U9b is 127mm high so there is no reason it cant be lower.
Improve the fan design and make them pwm. Increase their RPMs to over 2000 RPM at max and make them have more S.P. This may make more noise but this be offset by the Pwm function and improved cooling when overclocking, especially with Haswells.
The mounting system as of now is ancient and MUST be improved. Noctua's secu-firm system allows you to mount the back-plate and then the cooler, thus eliminating the need to mess with the backplate.
A mounting system like that would allow mush easier installs.
Do this to the updated cooler, and it will be a winner