I've only had access to one decent electronic caller, an old Foxpro belonging to a friend. It eclipsed the el cheapo no-name electronic I bought a number of years ago, but personally I just like using mouth-blown calls far more. I'd rather shoot one dog that I called in with a mouth call than three that came to some battery-powered electronic gizmo out in the field. It simply feels like more of an accomplishment, more of a hunt.
I think a motion decoy makes a huge difference, but there's almost always enough wind to animate a feather on a string. I have a couple of battery-powered squirmy things, but I just don't like having to walk out into the field and set them up. I know I've spooked a couple of dogs that way; how many more did I not know about?
Again, a single or a couple dogs taken with a minimum of simple gadgetry is much more satisfying, IMHO, than a larger number fooled by electronics and servo motors and batteries.