HP and Dell are each taking different approaches to sustainability. One is emphasizing removing toxic compounds from manufacturing the other is focused on recycling through take back programs.
HP is better than Dell at removing toxic compounds from their designs. They have reduced PVC and BFRs have completely phased out beryllium and other compounds.
However, Dell is working with the EPA on the National Strategy for Electronics Stewardship. The Dell and the EPA are promoting the use of certified recyclers for electronic waste. The goal of the Strategy is to “encourage electronics manufacturers to expand their product take-back programs, and use certified recyclers as a minimum standard in those programs.”
Both HP and Dell have good competing sustainability strategies, but the marketplace of the not too distant future will not tolerate an either or approach.