I prefer to press seams open. I don't use patterns that tell one which side to press a seam. When I try to press to the side, I always end up with seams that should have been pressed the opposite way.
Always pressing to the dark side ends up to be wrong with the construction of some blocks. That results in seams that are twisted. I just eliminate that problem with pressing the seams open and shortening the stitch length to 1.5. I haven't had any problems doing it this way.