I stopped at a local, very vermonty, which is to say lots of lawn and stuff, shopping center the other day for some ice cream, and the grounds were being mowed by an electric walk behind mower with a stand-on sulky. I imagine it was pretty expensive too, but so are the pro quality gas ones, and this one was nice and quiet, and of course, simple. No idle, no noise at all when moving, until the rotary blades started up.
I suspect that it will take some time to pay off, but not so long if there was a need for a new mower anyway. With the cheap power, and essentially no maintenance other than sharpening the blade, I bet it works out pretty well.