I have had two Sightron target scopes, one back about 12 years ago was great, one about 6 years ago was not. These were SII IIRC. 1" tube, tall knobs, AO. The last one, I put out a regular 1" grid rifle target at 200m and could not get it real clear even with the AO. So that was glass clarity. For a cheap scope I do like my STAC on a 22lr.
I got in the Burris yesterday, and put it on the 25-06. I like it quite a bit so far, but have not put it to use. Seems like an example of how some things can get better over time.