I have the US Optics spotter. It is difficult to use off a tripod as mentioned above. The small eye relief and adjustable objective (as opposed to a side focus) seem awkward when used traditionally, but I'm trying something different with it. I mounted it on an old stock I cut down and drilled a hole in. I use a benchrest bipod off the bench or prone, and a seated bipod if the other is too short or to sit. I also mounted a monopod on the rear of the stock and built up a proper cheek weld for it with pipe insulation. This is new to me and I haven't used it in the field but it seems to me this method of use draws from the steady hold skills I already practice and is actually nothing new.
I think the Mil reticle and the FFP are essential.
Also, the glass is just a bit better than my Lupy Mark 4 scope but real close to my NF scope. The test was if I could read sheets of large print set at 150, 175, and 200yds in direct sunlight, no direct sunlight, and low light.
My intended use is not to see holes in paper but to watch for trace and/or impact so to then form an objective correction for the shooter. I don't think the higher magnifications are necessary for the stated purpose. If anyone has any comments or insights please voice them.
JoeZ