I've noticed my pressing habits to be evolving. it's what you all have said. Nesting is wonderful and helps my accuracy on bigger pieces. On smaller pieces, if my quarter-inch seam got a little too big, pressing open can give me that extra millimeter I need so my final block comes out big enough. But it is harder to get pressed-open seams to intersect. So, it depends on the project (and how I'm sewing that day) what works best.
I did watch the Leah Day link -- love "myth-busters" but as always with that kind of thing, was disappointed. She did not dispel the "myth" that pressed-open seams are as strong as side-pressed. She simply said "see this seam? I've been playing with it for five minutes and it hasn't come open." She stated the stitch length has to be quite small for the seams to stay together. She also stated that side-pressing is "messy and lazy," so her opinion is clear. I suspect none of us are "messy and lazy" with piecing regardless of the way we prefer to iron. My own pressed-open seams do come apart if they are not back-tacked. The side-pressed seams don't. This is not usually an issue since the seams will be sewn over by adjoining pieces anyway.
In short -- factor in stitch length, size of pieces, number of joining seams, and your personal preference and experience.