Vortex and Primary Arms Red Dots

AIM Surplus just posted the Vortex SPARC scope in their Facebook updates.  I'd never heard of it so I'd checked the manufacturer's page.  A little searching on the forums seemed to have mixed reviews, but the negative ones weren't by people who've actually used the device--just people who prefer Aimpoint's or Trijicon's offerings.  People who actually own the sight seem to like it.  One post referenced a Primary Arms red dot, saying that if you're not going to go with the gold standard you might as well go with the el cheapo solution.