I have used a RCBS ChargeMaster for several years and it works as advertised......accurate to +/- 0.1 grain. It would give an ES of usually around 20+ fps since there is a small variance between each powder drop. Plenty good for most calibers used for hunting out to somewhere in the neighborhood of 500 yards. YMMV.
My AutoTrickler v4 and A&D FX-120i scale arrived about 3 weeks ago. It is definitely a step up in speed and accuracy. Now seeing ES between 6-15 fps and single digit SD's without doing any extra trickling or weighing of the powder. Didn't change anything else. Same brass, powder, bullets, primers and reloading process. I was a little challenged with getting it calibrated since there are several settings in the app but Adam MacDonald immediately replied to my emails and has since done a video on YouTube on calibration. The engineering and precision of this device is phenomenal. A single kernel of Varget weighs 0.02 grains and it drops to the same weight or one kernel more......every time. There is a green light that indicates the powder drop is within +/- 0.02 grains of target. There is no way it will drop anything less than 0.02 grains lower than target weight but can drop more than 0.02 grains higher if not calibrated quite right. I think I had some static electricity issues when I first got it, which Adam indicates will go away after using it......and it has. You will not get a green light if the weight is more than +0.02 grains from target weight, so need to watch the display on the scale to see how much over and whether you want to accept this amount.
This has made reloading more enjoyable for me since I hated to weigh powder a second time on a beam scale to get the accuracy I was looking for. No more. I think he has a real winner here. If you need or want this type of accuracy and don't mind spending a little extra, I would highly recommend it.
AutoTrickler v4
The new RCBS MatchMaster is $899. I haven't used one so maybe someone that has one can share their experience with us. I understand it operates on the same principal with a large and small dispenser tube but not sure of the type/accuracy of the scale they are using.