I own a stack of Leupolds and 2 Nightforce. The Vortex scopes are a great value for the money, but they are still a budget scope. You won't notice it until you have spent a day behind a Nightforce, Zeiss, or some of the really bigger dollar scopes (March scopes go up to 60x and $4000)! It isn't just about image quality to the edge of the glass. It is more about the strain on your eyes. If you look at a target or varmint at 1000 yards for a half hour, many of the upper mid priced scopes will serve you well (Nikon, Sightron, Burris, and lower grades of Leupold.) If you are sighting for a 2 or 3 man team you; can be in the glass for an hour and a half easily at a time, and eye strain starts to accumulate and a full day builds into a raging headache!
The bigger the objective lense, the more light from the target image is gathered. (It is a lot more complicated than I care to type!) But in Nightforce the difference in a 50mm vs. a 56mm objective lense is 20 to 25% greater, but the cost is only 5 to 10% more. Many courses have steel plates in the trees/shade or on purpose run into twilight. Plus cloudy days consume light like teenagers at a pizza buffet!
As my eyes have gotten older (62 now) I enjoy more magnification. A 5" plate at 1000 yards in a contrasting color is visible at 10x, but 20x or more is much easier on me! But one of the problems is steel plates that are 8" and under turn grey with lead splatter as more shots are fired, plus varmints are grey/brown to start with. You end up looking for shapes that blend in.
If you stay with the game, you will want the bigger lense and more powerful scope and of course the best glass. So do you spend $400-800 now and replace it for the next year, or do you spend $1700-2500 up front. Only you and your wallet can make that choice!
ADDED NOTE: I have a 20x, 2"objective, Varmint Unertl, They are from the 60's and 70's and are still hard to beat. Fantastic condition examples should cost you in the $800+ neighborhood. They mount totally different and finding gunsmiths to do the work is getting very difficult! But worth it!!!
If you are staying in the 400-700 yard range, stick with Vortex or their rivals, but if you are after targets out to 1500, you need scopes that cost a small fortune!
Ivan