I have an old Makita GEO600 grinder, made in Japan. They may not be made there anymore. It has done a lot of headwork as well as seen plenty of general use in the shop. It has been a great tool and still works well. Also have a Snap-On PT200L air die grinder which I like and use a great deal. Variable speed paddle and not too big. It has been replaced by the PT200AL. Both tools are large enough to be used 2 handed for control.

If the results don't match the theory, change the theory.