Re: 90% of the performance, half the price?
For $500 - $1000 value, the Sightron SIII gets the nod in our book. For $500 and under, the Vortex Viper would be our choice.
You learn a lot about a company when you see their best stuff, and see how it stacks up.
The reason why the SIII gets all the accolades is b/c it is Sightron's BEST scope. You never have that many positive comments about Lupy rifleman or VX-! or Bushnell Banners or Sightron SI or other lower end scopes b/c they are of lesser quality. They are still decent, but better alternatives exist within the company's product lineup. The SII Big Sky are not quite an SIII shrunk down in a 1-inch tube, the SIII's objective lens polish, coating, and arrangement are better in the SIII. I suspect the erector lens assembly is similar. The SII Big Sky are excellent scopes.
Vortex Viper continues to get overlooked but if the reticles and features of the scope appeal to you, then they are an easy choice. 90% of the performance of the best for a third or fourth the price!!
Anyway, these are my personal choices.
Can't comment on the Clearidge Ultra b/c I've never seen one.
"See Better, Shoot Better"