I'm not one of those who presses one way or the other as a rule - it depends on the quilt. If pressing to one side helps match points by nesting the seams, that's what I'll do. However, I recently made a quilt for my LQS owner as a shop sample, and the directions said to press seams open. Since it was her quilt and not mine, I followed the directions exactly. When she quilted it on her Gammill, she hugged me for pressing those seams open. I guess it made it much easier for her to quilt.