I think the 6-24 PST would make a great choice for what you're describing. I like mine quite a bit better than the 4-16's I had.
However, if you do much close stuff, the 6-24 may not be the best choice. While on paper 6X isn't bad and it has a decent FOV, the 6-24 is much less friendly to use on 6X than the 4-16 is on 4-6X. If you need something with a better bottom end, my own personal choice in that price range right now would be the Weaver 3-15 EMDR.
But for primarily 500-1000 yds, I don't think you can beat the PST 6-24 if you want FFP.