I have the Smith Long Range sight, it came with a defective peep slider that had the hole a little closer to the top edge, it wasn't centered, so to my 60yr old eye looked like a notch instead of an aperture. I finally got Smith to send me a peep slider that wasn't defective after several months, but I haven't shot it yet. Bernie (dodd3) has old eyes(over 50 IIRC) and he shoots his real good, seems to me 12-14" groups at 600-800yd. I dunno if I'd buy a the Smith sight now, it's $200, a good vernier sight isn't much more, and some are less than half that or the Marbles tang sight sight which is $120, but I dunno what kind of range can be had with it, I have one for my 38-55 Target, but I only have a 300yd range to shoot at, so I don't need anything for longer stuff.
Tim