We own both the Vortex and the Steiner. My wife has had the Vortex for almost 4 years and has several thousand rounds through it, i have had the chance to use it on occasions.... I bought the Steiner after I sold my PH and have a couple thousand rounds under it this year...Thoughts....
Both have proven reliable and we have not had a mechanical issue with either optic.
The Vortex has been used as a hunting optic and a match optic. My bride packs it everywhere and it has plenty of character to it these days.. The scope's tracking is repeatable and the large spacing with the 5 mil turrets are solid and as she says, "I can feel and see the adjustments when I am in a hurry and when my hands are cold".
The power adjustment is smooth, but a cattail was added to aid in the speed of adjustments. The parrellex works as it should and the the image is clear. We both prefer thicker reticles, so we don't have any issues with the reticles in either optic... Though my wife prefers the open reticle of the EBR2B, while I prefer the solid reticle in the MSR.
Steiner...You can read my review here:
http://www.snipershide.com/shooting.../191151-steiner-5-25-my-initial-thoughts.html.
Compare them. Both are very good, they are several differences in features... 5 v 10 mil turns, Steiner has windage stop at 6 mils, Vortex keeps tuning...Yes, you can buy the Vortex with 10 mil turrets. Eye box is much more forgiving in the Steiner and I prefer it, but if the scope and rifle are well setup for you, the tighter eye box of the Vortex is hardly noticed.
We have not had any issues seeing and engaging targets from 15 to 1580 yards with either optic.
Repair work, both done on shore and the reports for both company's are excellent. We have not had to use either for these scopes.
My thoughts, try to get time behind them both and decide which features you prefer, you won't be upset with either.