I use a RCBS beam scale -same one since 1970. I tried the digitals but I guess its hard to retrain old dogs...lol. I did take the scale to work a few years ago and had the scale calibration guy check it. It was within .2% from 3 to 250 grains. I also bought a set of certified weights that I use to verify function. I load from 4 to 60 grains of several different powders for the calibers I use.
I have three, two "balance" scales A "Hornaday" and a RCBS which agree with one another and an RCBS electronic which does not agree with either. I use one of the balance scale[s] when measureing powder charges and the eletronic when weighing projectiles.