Things I liked: Very convenient to use in any basic shooting position, i.e. using the offhand standing hold it is easy to adjust by sliding the forearm holding hand rearward slightly and adjust with the thumb (if right handed), or the fingers if left handed). Well made product.
Things I would have changed: Nothing
What others should know: Go slow when installing, ease it on; nice tight fit. Set screws not needed for my Leapers SPC3-U312A0IEW but a nice touch. I am not so concerned with the accuracy of the distance markings (but they are close) as I am about the virtual lack of parallax when the target is focused. I've bench checked the Parallax at the "target focused" settings and found those settings to be very close to correct. Not an Olympic shooter but I stress over "One Hole" groups and this item is very convenient for eliminating the parallax error at varying distances without having to reach up and grab the front of the scope or having to use the thumb and forefinger for the SWAT knob.