The housings are different. Specific tunes can be ordered. You can get, for example, a run of the mill, ok performing tube in your PVS 14 or you can get a high spec white phosphor tune in your PVS 14 that will blow your socks off. Less choice for non standard units like the NYX 14 typically. But after the tube, the housing is everything. Choices regarding how you mount, duals, bridges, bayonet vs dovetail, etc, are much broader with a PVS 14.
I have two PVS 14s with high spec 28+ SNR Pinnacle tubes I would sell, with TW helmets and good mounts if you are interested. I also have a Crye Nightcap I would sell. Let me know if you are interested and I'll PM you specs and prices and the source I got them through, which will show the price for new versions. Spec sheets are dated, so you can confirm mine are't very old.
JPK