Product review (4 stars): amazing results but watch out for pitfalls
this kit is evolutionary in the quest for the proper ice maker water feed. The only thing that prevented me from giving it five stars is fair instructions and non-existent manufacturer support.
Like another reviewer I had trouble moving the valve handle at first. The valve comes in the open position and after several firm attempts and considering the aid of a pair of pliers (which would have likely broke the thing) I gave it an "with all my might" try and it moved and after this moved with ease. The directions on the valve don't help, There is an arrow pointing rotational travel toward off and the same toward on, rather than detente indications of where the off and on positions are. Absent the knowledge of these positions and the hard actualization makes it easier to break the valve if you seek help from pliers. Know this: the valve comes hard against the open stop and you struggle mightily toward the closed position only. I swear trying to open the valve at first was as hard as turning it against it's stop as it was away from the stop.  Again, once it moves for the first time it moves with ease and I hope after reading this you don't break your valve,
When I say fair instructions, they say to make a witness line 1-1/2" away from each pipe end and push the valve firmly onto the pipe up to the witness line. But both ends of the valve fell 1/4" short of the line again with the trying mightily thing. It held pressure  but I had anxiety that the insertion had stuck prematurely without bottoming.
Finally, when I say non-existent manufacturer support: searching part number of the kit or the included valve on the mfgr's web site shows zero results.
Oh yes, my installation was with 1/2" copper. There was some discussion in the blogs if it worked with copper and yup, worked with mine.
Other than these wrinkles not a drop of leakage once installed under pressure. There is a 3/8" gap between our counter top and the cabinet tops so routing the included pex line was a snap. I used "u" clip clamps to fix the tube. Good luck with yours and I hope this helps.