I've had the OP's RCBS scale for over a year now. I bought it because my Hornady powder drop sucked with stick powders, like varget or 4064.
I have checked mine against a lab 0.001g scale, and it does well within its reported limit of +-0.1gr. (mine usually measures +- 0.06 gr., with some variation in there).
As for the scale part - vibration will throw it off. I originally positioned it next to my press - but realized that top stroke caused some table vibration and messed with the scale. now it sits on a stool and no issues. It is important to turn it on and let it "settle" for a few minutes, then calibrate before use at each session. I also periodically re-zero to avoid any "drift" which is pretty normal in electronic scales (I re-zero every 50 rounds or so during an extended loading session). As for the trickler, it does pretty well but you have to pay attention to it. If it comes up on the limit too quick, it abruptly stops, then beeps like it's done, then shows +.2 or more over your limit. This happens maybe once every 15 rounds, but less often with spherical or flaked powders. Lesson here is don't go pick up just because it beeped. wait for it to show the weight again after it shows the count.
Overall - great investment. My previous setup was to use a Hornady drop measure, try to get just a couple tenths grains under weight, then use a trickler to come up to my target. Very time consuming when loading a bunch of different weights for testing - screwing with the drop after every 5-10rds.