I have the Sightron SIII LR 6-24x50 which I purchased from Scott @ Liberty Optics In 2011. Mine is mounted on a Cooper 57M. I have not used since I have had my 70 year eye overhaul. I can tell you that the glass is really very crisp & clear but the eye box is VERY tight once it is set over 16. After that it took me what feels like for ever to set my cheek weld.
Yes, I know it is not the exact model you asked about but just some feedback about Sightron.
I have several siii, s tac and a SV. SV is a very nice scope dual focus knob is worth every penny. Glass is alittle dark most of my siii's are brighter on overcast days. parallax adjustment makes up for those cloudy afternoons. I'd really like to try new HD glass model!