From the relatively well-rated products that I researched so far, I get a lot of differences in opinion. One person will say that they are the best and softest sheets ever, and yet another will say that they are stiff and feel like sandpaper.
I actually picked up a 525 Pima Cotton Sateen sheet from "Bed, Bath and Beyond" a couple days ago, and immediately found it to be uncomfortable, stiff and scratchy (almost all of my other sheets are softer). I've since learned that you're supposed to wash it a couple times (don't even get me started on all of the baking soda, vinegar, etc. tips I've been reading about) to soften it first (which I will do tomorrow). I will probably return it if it doesn't improve, and order something well-rated on Amazon. If someone has some knowledge in this area, please let me know.