To me, this is pretty simple. There are a number of decent optics makers under $1000 or under $500.
Vortex, Athlon, Arken, Sightron, etc.
That said, you get what you pay for. You buy a $200 long range scope and it will not be very effective mechanically likely. Over $500, I think you could get something that will take you a ways.
The key is to get your hands on it.
Is it FFP? Can you work with the reticle? Really think about this? There are some reticles with bizarre scales, business and odd zones that are not really usable looking at normal dope! There are also reticles that disappear at 3-5x. There are full illuminations and center dot only illuminations. I guess my point is really study the reticle with realistic shots. Will it work?
For example, (270 Winchester w/ 140 SST) Nightforce has a Mil-XT reticle at 1 mil drop(300 yards), you can have up to 3 mils wind. 3 mils wind is about 60 mph…..Do I really need the tree to fill up that much of the view?….or is 30 mph plenty of wind hold? The tree is 12 mil tall. That gets me to 1200 yds. I think I'd much rather dial past 700 yds. What is this excess causing? Excess lines blocking my view and no thick part to the plex for low power aiming. To someone that reticle is great. To me hunting it looks like puke in the optic.
Do the turrets feel good? Do the turrets adjust in the correct amount?
Glass good enough on target?
You can check these things before you solidly mount it and really "own" it.
I have been really happy with 2 Vortex PST Gen 2's. I was less happy with a Burris XTR 2.