KLR said:
I've used Sightron's SII product since 1999, and have had success with it in matches. I would never use anything less than a Leupold VX3 (or VX-III, or Vari-X III, see the trend?). Leupold is the most overhyped, overpriced product in the market; they do a brilliant marketing job, but they've made a fortune on the VX2, despite it being mediocre.
When I bought my first Sightron SII, it featured a one-piece maintube, fully multicoated optics, incredibly reliable click adjustments, and a lifetime warranty.
The Leupold VXII featured a tube made of sections, fully coated (but not multicoated) optics, friction adjustments (let's see, when I use my dime to turn this stupid thing, was that about 1/4 of a minute, or 7/11 or WTH?), and a lifetime warranty.
The Sightron was made in Japan; the Leupold in Oregon. The Sightron cost less, for a better product.
Your mileage may vary (no pun intended).
One last comment, in case you thing I'm being vague: I paid $244 for the SII referenced. I would not sell it for $500, because I have as much faith in it as any scope I've ever owned, including scopes that cost almost ten times more.