One other nice thing about the Harrell is that it has click settings that are ultra-repeatable. No micrometer setting, stem measuring, etc. is needed. Even considering climate, if I set my Harrell to a number (say, 43), I'll get virtually the same charge, or within a 10th anyway, with the powders that I use regularly (H322, 748, Varget, even some 4831 on occasion for the thumper).
Consider if you haven't handled one, finding a buddy who has one. They are mind altering:-)