I'll add to what has been mentioned in that it's very hard to beat a beam scale for CONSISTENCY. Accuracy of it could be debatable as in maybe it is off a tenth or two from what it reads but it will consistently be the same from charge to charge and session to session if you take a couple steps to keep it that way.
My process is to throw the charge with an RCBS charge master setup then verify and trickle with the beam scale. I outline a spot on my reloading bench to set the beam scale the same every time. I zero the beam scale then use a check weight to verify the scale is set. As you weigh the charge pay very close attention to the graduation marks, don't breathe or let a draft blow over the scale as you weigh. By doing this I can achieve consistent charge weights to the KERNAL of powder, my ES and SD is very consistent. Doing this has also showed me that the digital scale can drift +- three tenths giving a total of six tenths variation in a loading session. The beam scale variance is less then one tenth.