Hey Kjohney,
Well depending on where you were intending to get these new machines, might have some bearing on it. There are lots of good ones out there, and different ratios, and locking.... If you walk into a shop and ask I'm sure you will get differing opinions, but most sales folks will let you fondle one before you buy. If you purchase online, then you should stay with one of the better names. I've changed a few in my time and lean towards Grover but Gotoh are awfully nice also. I try to stay with whatever fits the screw pattern so the wood doesn't wind up looking like swiss cheese, exposed holes are tacky... even if they are in the back. I would know they were there and it would bother me.
As to the electric ones... sorry haven't seen those, but you might be able to rig up a fence charger.....
Take Care; Doug
"what is this quintessence of dust?" - Shakespeare