It doesn't matter what powder measurer you use, they are only accurate to one degree or another. Your consistancy and technique are what matters. Any change in the process will affect your results.
Here's an example. I use a Redding 3BR. When I add the powder and adjust the micrometer, I will throw about 5 charges, THEN weigh a charge. I then make another adjustment, ten throw about 5 charges, then weigh one. Everytime I throw a charge, I return the powder to the measurer.
The reason for doing it this way is that the poweder settles differently with every adjustment of the micrometer. For example, I had a friend over a week ago and was teaching him how to reload. I had him throwing the charges and measuring every one on my scale. There was a point where he had to add powder to the measurer and forgot to adjust it. After a few charges, he said, "you know, this thing is way off all the sudden!" And I instantly knew what happened.
I guess my point to this is that if you keep your technique in check, your measurer can be very accurate, but measuring every charge is VERY important.
Electronics measurers are supposed to take care of these problems, but I haven't used on that has been fast enough for my liking yet.