I have a a 58v Echo cordless. 16" bar. Cuts like a dream, quieter than the gas model and fewer things to go wrong. I didn't get it for 'green' reasons, I just am really bad at keeping small engines running well. With this thing, all I need to do is keep the chain and bar maintained. The battery is not that big...sure, bigger than some, but the whole thing is maybe 13 lbs.
The drawback right now is cordless only go up to about 18". That is fine for most of my work, but I am hoping technology improves so I can get a 24" bar on a similar model.