When I got my K2 router the salesman kind of pushed the tool height indicator on me. I got the feeling they had just developed it, and he wanted to sell units. I was (still am) new to CNC and didn't know what I needed, so I agreed to try it. I hooked it up and played with it for a few days. It could be my inexperience, but I decided that it was just as quick and easy (and as accurate) to set Z0 using a feeler strip against the workpiece. Even though my product requires 8 tool changes, I just couldn't see that using the indicator made things any quicker or easier, so I sent it back.
I love the K2 machine. I've been meaning to write a review but never seem to get around to it. My work is all 3D in extremely hard woods, and the machine has met every challenge.