The term is "collimation," and it can't be done with bridged PVS-14s, and can only be done to a certain extent with articulating goggles.
I'm all about saving as much money as possible and not spending any more money than necessary to accomplish whatever it is that you're trying to accomplish--however saying that bridged PVS-14s or biocular devices are "just as good" as dedicated binoculars is just as disingenuous as saying that if you don't spend a bazillion dollars, you're definitely going to die.
This doesn't mean that bridged PVS-14s or PVS-7s suck and they're useless--they're plenty serviceable, and can be used very effectively. However, there's a reason (e.g.,) pilots aren't allowed to fly with either set up, and are required to wear a set of properly built binoculars. There are differences--the question is whether or not those differences are enough to justify the cost for you as an individual, they may or may not be.
If you want/need the capability to split your goggles into individual monoculars, the AB Night Vision MOD-3Bs are a fantastic option--they can function as a dedicated binocular, but you can use them as monoculars when needed.
Beyond that, we've found that the best way to do business is to give good advice and education and earn loyal customers--not by "upselling" one or two expensive devices to a revolving door of new customers.
We sell PVS-14 bridges. For some applications, some limitations, and some customers, they work great, and might be the best option--if that's what you need, that's what works for you, or that's just plain what you want--we're happy to help you. In general, however, I recommend against them.
Used PVS-7s are probably bar none the cheapest consistent way to get into Gen. 3 NV. Better Gen. 3 PVS-7s than no NV, or scraping the bottom of the barrel of overseas-made Gen. 1 and cheap digital devices.
~Augee