I like most people learned to press to the dark side however after watching Shar Jorgensen she always did open seams then after making one of the quilts she made on the show I absolutely understood the whole open seams because of the bulk. So it depends on what I am making.

I have pressed open on a couple small sample quilts but do a zigzag stitch down the seams so they aren't exactly a sitd but still connect both seams. I prefer seams to one side.

I press to the dark side, and swirl the merging points. But I have pressed open when the pattern calls (elizabeth Hartman's Fancy Forest and other patterns are pressed open because of so many small pieces)......but then I had to do an allover quilt pattern because I could not do a stitch in the ditch

I much prefer seams pressed to the side, for the reasons mentioned, and also because they seem to stay in place better on the back of the quilt. I also prefer the look of seams pressed to the side on the back. I do follow directions with modern quilt patterns and press open when specified, and I'll press open when it seems to make more sense. Right now I'm doing a border with overlapping squares, and it made sense to press the seams open where the like fabrics came together.

I almost said I ALWAYS press to one side. Then I remembered I just started piecing the big block on Bonnie Hunter's En Provence. I am pressing the longer seams open because there are SO many layers! It is such a busy pattern, I think I will do an all-over quilting design anyway. No need for ditches for SID. I guess I better learn not to say ALWAYS and NEVER...I will prove myself wrong!

I press open if I don't want anything specific on the block to stand out.
What ever piece you press onto will then catch the eye when finished.

I normally press the seams to the dark side. If the directions I use, or it make sense, I press open.
Normally, the only seam pressed open is in the binding. I think that is better there.

I hand quilt too. It IS easier.

In my opinion, pressing open the seam might cause the thread to break with hard use or frequent laundering. I have always pressed the seam to one side.

I always press to one side unless I have a bunch of seams coming together making it bulky. Then I'll press them open but that is about the only time I press them open. I don't think there is a right or wrong way though. Just whatever you like & works for you.