I had an electric mower when I had a very small lawn and for a lot of reasons I loved it. The biggest downfall to them is that when they break down, they typically cost more to repair than just replacing them which is expensive. I now have a little more than 1/3 acre with quite a lot of grass and the electric mower just wouldn't get the job done. With a lot that big, assuming some significant portion of it is grass, I'd go gas.