I have had several different variations; both electric and hydraulic work well. It really boils down to what works best for you. I have used Mec/automate, P/W-automate, and settled on P/W-Spolar hydraulic. I would probably go Spolar loader, but won't give up my shell feeder. With the foot control, you just watch the stations, and put in a wad at the right time, hit the throttle again. Out pops a perfect shell. I have not seen any significant differences in the loaded shell between any of the units, but do find my reloads with the P/W to be incredibly consistent.
I am sure those with Mec/new automate find them to work well. The big advantage to those units are the ability to put them just about anyplace and they work. My reloader/hydraulic unit sits on an industrial strength bench. I was thinking of getting a mec/automate unit to load in California since I would not be limited by where I could use it. However, I have not been able to run myself out of shells so I decided that was not necessary.