Absolutely gorgeous quilt! I always hand stitch the back of the binding -- it was the only cure for that problem that works every time. I am going to experiment with the old fashioned method of binding of pulling the backing over to the front (backing is cut 1.25" bigger than the front and folded in half). That's when I will try the decorative stitch on the binding (it would be sewn on the front and you'd have more control).
I love the colors and quilting of your quilt! SIGH!