One thing I don't see mentioned here is...if you want to stitch-in-the-ditch with either machine- or hand-quilting, there really isn't a "ditch" if you press the seams open. I also think pressing to one side is the easiest way and the most accurate way with the advantage of nesting seams. On rare occasion do I press them open. Just lately I tried pressing all of them open on a simple quilt just to see how a like it. Nope! Will stick with pressing to the side.