I have some S1 and S2 series Sightron scopes and like them, with the exception of the 3-9x32RF.

S1 1x20
S1 2.5x20
S1 2.5-10x44
S1 3-9x32RF
S1 3-9x40
S1 4-12x40AO

S2 2.5-7x32
S2 2.5-10x32
S2 3-8x42
S2 3-9x42

They seem like good scopes, but they don't seem to get a lot of love. None of my friends own any, even though I've recommended them, recently the 4-12x40AO S1s.