Oooh pressing to the dark side sounds so ominous!! LOL. I personally press to the side for everything, but I know some great quilters that press open. I think the praise for pressing open comes in because it really reduces bulk when you press open, and depending on the pattern, this can be a HUGE benefit when quilting. There are a few patterns I will press open for this reason, but mostly to the side.
Cheers!
Rachel