I personally machine sew to the front; fold over and hand sew to the back. That said...there are some charity organizations that I've contributed to that require 100% machine work. I think most people's issue with 100% machine sewn bindings is that they have a tendency to not lay 'flat'. I've had that issue myself. I think the trick is, if you have deco stitches on your machine, do the straight stitch on the back of the quilt; fold over to the front and find an appropriate deco stitch that will have the front of your binding lay 'flat' - if that's what you want. Be it a plain zig zag or something else. Personal opinion is that those folks that are unhappy with 100% machine sewn bindings is because the machined edge is just not as 'flat' as a traditional hand sewn binding. Just my opinion.