I also purchased a Vortex 6-24PST,FFP, ect. and put it on a MDL22 Cooper VDM, 6.5-284, 26", 1/8. I like it fine so far. I look at it as getting everything I'm going to use in an optic under $1000.
The Nightforce is more scope for that $600 than you may realize. It's 34mm, rather than 30, and the zero stop is much better than the Vortex, system of stacking shims into the turret to make an approximate zero stop. The Nightforce also has quite a bit more internal adjustment, than the 30mm PST.
AS for the optics my eyes can't really see any difference, but my eyes are a joke nowdays.
With the Vortex, you get nice features, for under $1000, but don't expect the refinement of a scope costing almost three times as much.