Really exciting technology indeed.
As for environmental effect: At least additive manufacturing means a lot less waste than traditional methods. As you don't cut off parts which are then left as waste.
I am looking forward to see 3D printers become more user-friendly too. So that anyone can have 1 at home and simply print out new clothing from an "App Store" of clothing designs. Where you basically just pay for the designers creativity and the right to use his code, and not for tailoring.