I've had 2 Sightron SIII's and they have been fantastic.
Just a little education for those seeking a Sightron:
Just over a year ago, I did see another SIII that looked a little bit different than mine, so I investigated. What I found upon calling Sightron is that even the SIII's were updated a while back (maybe a year ago). The newer ones have much better glass and some other internal improvements.
So, it was the older version of the SIII that I saw, and btw, I didn't like the glass quite as good on it. It wasn't bad, but I could see a difference.
So, my point is that the new SIII's are EXCELLENT and have EXCELLENT glass and tracking. For the money, I don't think you can beat it.
If you find a used one that someone wants to sell, make sure it's the newer updated version......There are ways to tell, but I can't remember what they are. If not sure, call Sightron first to check.