I machine sew the bindings down. I do a LOT of charity quilts and children's quilts. Machine sewing is more secure to last washings and abuse.
I sew to the back and bring the binding to the front and topstitch. It looks nice.
For my own quilts, for myself or family gifts, I will do it traditionally with hand sewing. Then I use the school glue to hold it in place so I dont get stuck with pins.
Jean