I have one older Sightron and one new one. The new one has the illuminated MOA2 ret which I think is better than the milldot ret.
The real new price for a Sightron is £1100 and there are reasons you don't see them for sale secondhand!
They are 10 ounces lighter than a BN and there were more than two on last years GP circuit.
The problem with the Leup's is the image is too good and stays in focus more than an FTer would want. This is not a design fault, but a sign of expensive top quality glass. But as I only shoot FT, I quickly sold the Leup that I had.
As for the light transmission through a Sightron, the image is brighter than my own eyesight at 25mag, which I consider excellent and made my BN look like a chinese Tasco.
Anschutz 2013 MEC1 .22LR
Miroku 3800 12bore