As I said - I press most of mine open and have done for many years. No disasters yet, and the finished tops are much easier to quilt either by hand or machine. I no longer do my own quilting, but I still prefer the "flatter" look that can be achieved by not having those bumps where seam allowances cross/meet.
When I teach new comers to quilting I have them make a couple of small quilt/placemats using four patch blocks in a simple Irish chain pattern using quite heavy homespun - one with seams pressed to one side and one with seam pressed open. They learn that to one side makes the seams "nest" nicely but produces a "hump" of seam allowances, and that pressed open requires more time and patience and a differnet technique to match seams. Then I tell them to use the one they prefer, or switch between the two according to the style of quilt they are making. I generally recommend using one method throughout each quilt just for appearance, with the sole exception that I normally press all my seams open except those on my long plain borders borders. But it's not a hard-and-fast law. I would have no problem with switching from one method to another if construction called for it.
I am making a scrap quilt ATM and most of the seams are pressed open. But I used all charm squares and just a few are a tiny bit small so I double stitched the smaller seam allowance and pressed to one side. If you look real close at the blocks you can see the difference but once it's quilted it won't be noticed. But I still prefer the flatter look and feel of open-pressed seams.