I'm sure this was debated, for me personally, I wish I could change between Metric, Feet/In, etc in the same screen where I'm working with Position and Orientation data. That is where those numbers matter the most and where I most realize I want to be in a different units settings. It feels annoying to have to back out to Setup to make that change. I think the button should just be to the right of all the XYZ data as shown in this photo. 
