Have you considered the Burris MTAC line? I have several MTACs and they are great. The 4.5-14 is on my .308 bolt gun and a 6.5-20 on my .223. There are 5 in the line: http://www.burrisoptics.com/mtac.html The top three in theline are mil/mil,
with adjustable parallax. They also have finger-adjustable turrets for windage and elevation that are zero settable and retrurn to zero.

The top end of the Vortex line is excellent, the ones under about $800, not so much.