The SPARC is mounted on my PS90.
My 2 cents on the SPARC:
pros - small, light, 2moa dot, doubler, plenty of mounting height options supplied in the box
cons - the location of the on/off switch, wind / elev o-ring seals are fragile
Overall, quite happy with the quality for the price. Really like the doubler and 2 moa dot.
Ex - Navy, Persian Gulf Veteran. Loved shooting the M14, 1911, M60, M2