With optics, you truly get what you pay for.
To a degree. I mean yeah, in general, the higher end optics are "better" on paper, but will the user see a difference?
Optics for rifles are no different than optics for cameras. The "mid range" stuff is fine for 95% of uses, and for those 95% of things, there will not be an objective difference between the two. A soccer mom doesn't need a 400mm f2.8 lens to take pictures of little Timmy playing soccer on Saturday mornings. The pictures will probably come out the same with the bargain 55-300mm variable the DSLR came with. Most people don't need a Nightforce or a USO to go make holes in paper with factory ammo on a one way range.
The professional photog who gets paid not to miss a shot probably can justify needing the 400mm f/2.8, because he uses it in extreme (low light, wet, dirty, etc..) conditions. Guys who drag their rifles into combat zones through the most extreme of conditions can justify the need for something like a NF, USO, or S&B.
If you are the kind of user that shoots factory ammunition only on sunny days at known distances, and babies your gear -- there is no reason to spend a ton on optics, because the additional $ will not result in any kind of gain for you. You probably won't find the limits of budget/midrange stuff, so there is no need to spend more.
If you are hard on your gear, shoot in all weather, frequently take classes where you're running and gunning, diving, crawling, and rolling around or you competitively shoot something like 3-gun every week, or you painstakingly handload ammo while chasing the mythical "5 shots in 1 hole" unicorn then yeah, you might find the limits of "budget" or "mid range" optics, and some of the additional features of the higher end choices would be justifiable.
As you increase in price, you tend to get (with optics in general -- a lot of this stuff is the same as camera lenses):
-Less fisheye/distortion at the edges of the lens
-Less discrepancy between real and advertised magnification (1x really is 1x -- not 1.3x, etc..)
-Slightly sharper in the middle of the lens
-Brighter/more contrast/less flare
-More shock/impact resistance (not from recoil necessarily, but dropping the rifle, banging it into stuff, etc..)
-More advanced reticle/turrets (FFP)
-Smoother focus/zoom mechs
-Better waterproofing
-Longer battery life
-More durable fit/finish
Just remember though, a lot of this stuff is subtle. You know how hard it is to choose between #1 and #2 at the optometrist, right? Your eyes are very adaptable. In my experience, the picture you see when looking through a NF is barely discernible from what you see when looking through something that cost 1/4 or 1/3 as much.
But anyways, OP, Vortex stuff is good. I think dollar for dollar, you get more of those features with a Vortex optic than you do with competitive offerings from Bushnell, Nikon*, Millett, etc.. I have a Vortex Crossfire II 1-4x24 V-Brite on my SBR, and it's awesome.
*I shoot all Nikon gear for my photography, and I think they are very good at making glass. However, a lot of their rifle stuff is 1" tubes, as opposed to the 30mm tubes everyone else uses.