Just going to throw out some more that doesn't really answer your first question but may still be relevant for those in the market.
I'll make it clear that I was spoiled as far as range finders go because I was issued a Leica with a tripod for about ten years.
When using the Vortex Impact, though they claim it will range out to 1000 yards I found that if I was attempting to range anything over 200 it had better be VERY reflective and at least the size of a stop sign. A stable rest helps to mitigate this but if you think you are going to be ranging an animal standing just a bit outside of a treeline at 400 yards just hand stabilizing the monocular, its not going to work.
