I am looking to upgrade my optics and I am throwing these two scopes around. I can get a really good price on a Mark 4 but I have been hearing very good things about the sightrons as well. I am building a long range rifle and in the near future I have plans on competing in F-class competition shooting. The Mark 4 would be the 8.5-25x50 with the TMR reticle or the Sightron SIII 8-32x56mm with the target dot reticle. Nightforce is not on the list because it's a tad out of my price range. I can get the mark 4 for a significantly lower price so that's why it's on my list.