How large are your targets? If you're shooting large, generous targets, which help you identify an aiming point efficiently, you can get away with much lower quality, lower cost, lower magnification optics. If you're aiming at watermelons at 600yrds, you need a lot more scope than if you're aiming at a 24" steel gong. Are you wanting a smaller objective "hunting scope" capable of longer range work, or a large objective range ready optic?
Assuming you're looking for a large body scope for shooting moderate to large targets, not game animals: The Vortex Viper HSLR 6-24x50mm with the XLRMOA is a very reasonable scope for 600yrd shooting, even on smaller targets. It's first focal, which offers a big advantage for guys shooting at variant ranges. The Leupold VX3i 4.5-14x50mm is a well priced scope, without the bells and whistles of some of the others. I prefer the Bushnell Elite 6500 4.5-30x50mm over the VX3i, for the clarity and brightness, and of course, the zoom. Bushnell also makes a 2.5-16x50mm version which is nice for a hunting scope, because of the lower bottom end magnification. The Nightforce SHV is a good optic for the money, and the 4-14x F1 version is another optic I favor over the Leupold, but it's a lot more expensive on street value - you'll get one for under $1,000 on sale though. I'm not a fan of Nikon optics, way too many headaches (literally) from my eye trying to resolve the edge distortion in their optics, or fighting with a 14x scope which can only be ran at 12x before things got wonky - their legacy products all had really poor internal adjustment ranges too, precluding them from use on long range rigs, although they've remedied that for their newer models (some of them). The Burris XTR-II line is good, although higher than what you're wanting to spend - I've used ONE Veracity scope which I believe was serviceable and I was happy to employ it, although lacking some of the key long range features of the XTR line. The Sightron SIII line has a couple viable models, no frills for their price range, but very serviceable scopes. Personally, for a $700-1,000 scope, I'm Nightforce, Bushnell, Burris, Vortex, then Leupold, and I'd wait for sales on any one of them before I tried saving money on any other brand.