I've been pressing my seams open for the most part for decades. Periodically I try the to the side method and I simply do not get the same accurate results. A lot of it just depends on what you are used to, me I use lots of pins and press all the time.
I'm currently working on a fan quilt. I do usually press curved seams to one side and I have been doing that. My fan blades are pressed open but all the other seams (including the sashing now) are pressed to the side. Just works better with curves.