Just got a second one. Used the first on a Tele build. The multiple heights included give plenty of options. Takes some tweaking but so does a standard nut and you don't have to worry about overdoing anything.
I put one on my Taylor 12 fret, it made a big improvement in string tone, tuning, and intonation. I'm now going to install them on all my guitars.
I bought this for a Washburn Oscar Schmidt OE-40B archtop guitar, on which the nut had broken when putting on new strings. I always wanted to try a zero-fret nut and was pleasantly surprised at how well it works. Perfect string height and tone.
I have a Yamaha F310 and the nut was cut real high. Looking around on the internet I came across the ZerO Glide and decided to give it a try. It was less expensive that having the nut cut or purchasing the tools to do it. Printed out the sizing chart and found the ZS-5 had the correct spacing. In less than an hour my guitar felt and sounded great. This is one hell of a product and glad I made the purchase.