I think green IT guides are important. But there was some interesting criticism from participants of the criteria of the rating system used in Greenpeace campaigns.
For example in smartphones (http://www.greenpeace.org/usa/wp-content/uploads/2017/10/Guide-to-Greener-Electronics-2017.pdf), Fairphone and Apple get almost the same grade, but Fairphone lacks the same level of quality control, which would make it hard to recommend Fairphone on that rating system alone. Makes it important to know what values go into a rating, if they align with your own.
#mozfest