When I first showed my home made tramming tool on the net, there were flaming crosses and death threats (just joking of course) because it bucked the trend of bits of bent rod and rubber necks with mirrors.
I was only showing a version that I had seen a chappie knock up many years ago to help him set up quicker in the production environment that he worked in.
Now a couple or so years on, where they have been shown commercially, it seems like that everyone and his dog wants to get hold of one.
I will just say one thing, they make tramming your mill a joy to do rather than a PITA.
Bogs