I've got one of the RCBS electric dispensers. I THINK it's the model you're referring to. If so, it's actually made by PACT.
It's "ok" if you're wanting to do some load development with a particular powder. It takes approx 5 minutes for it to "calibrate" to a new powder. once it does though, just inputing thedesired charge and pressing "dispense" is a LOT easier than trying to adjust a manual measure exactly .5gr or whatever increment your working up in.
Considering the speed..... I don't ever remember it taking 4 minutes to dispense a load. 2 minutes, yea probably
There's a little trick that can and will increase the speed considerably. I set my manual dispenser at least 2gr lighter than desired and then use the electric dispenser to trickle in enough for the desired charge. That cuts down on my waiting time considerably.