Some think it's the coolest thing ever - and would be willing to dash out more money for it (and usually it costs more). However, though, others might say it's some scam - targeting environmental types - and those with some guilt trip (over the fact hosting is a massive polluter). Anyway, myself, I love green hosting, but I have my doubts on whether it's actually making a difference.
Do I use it?
I use it for my main hosting projects. It's a bit more - but the "guilt thing" brought me into it.