Opinions are like ... everybody has one.
Balance beam scales are reasonably accurate but require good technique and they are slow but they do not require electricity.
I own a Dillon battery-powered scale, I would not recommend it - it is load cell type and doesn't hold a zero. It was bought for BR matches and it was never good for that.
I own two Denver Instruments digital scales, one good to a tenth of a grain and another one good to 0.02 grain. Both are load cell types. The first one is old but it is rock solid, the display is partly defective but I still use it to check other stuff. If you put something on it, you get an answer, fast, and it doesn't wander all over. If I zero it today, it will have the same zero in a week or a month. It doesn't care about electrical stuff in the area.
The second DI scale is much twitchier. It is also a load cell but it is hard to get a trustworthy reading - it drifts. It sits on my bench waiting for an application. I would sell it but I won't lie about it.
I own a chargemaster (CM) and I liked for a long time. The automation is good, it rarely overthrows. When it does, I can throw the charge into the powder hopper and get another one. It is reasonably accurate - I won't go further than that.
A few years back I bought a Sartorius Practum 213-1S. I would throw a charge with the CM, pour it into the Sartorius pan, and use a little battery-powered trickler to finish the charge. I loaded precision ammo that way for several years. I could definitely see the improvement on my targets - compared to the CM it cut my vertical in half or better.
Last year I bought the AutoThrow AutoTrickler combination from Adam MacDonald. It is a Rube Goldberg setup but it works as advertised and it is significantly faster than my CM-to-Sartorius-to-trickler method and there is less fiddling around. Put the little cup on the scale, wait for the motor to stop, put the powder into the case, move the funnel, put the cup back on the scale. If it throws an overcharge, I toss it into the powder hopper and do it again. I have two complaints: (1) I change charge weights and I have not figured out how to repeatably set the thrower and (2) In order to start the process, you need something on the scale that matches your desired charge weight and that is a pain. I'm thinking about making some weights that match the charges that I throw - pieces of brass or something.
Except for my first Denver Instruments, I did not have good luck with load cell scales. Even the CM is not super stable. If you want very precise amounts, fast, you are going to spend some pretty serious bucks. Fast, right, cheap, pick two.
