If quilts are machine pieced, it doesn't matter if you press to one side or press seams open. I've tried the open thinking it might be easier to match the seams, but, I didn't think so, with the seam going to one side and matching seam pressed the opposite way, butting them up really matches the seams easier.
Making a tube quilt I found you couldn't press to the dark side as the allowances went the same way.