The display is a Dell XPS 27 all-in-one. Yes, I've seen some disparaging of Datacolor, and some mixed reviews. Although I do strive for good color, and I regularly sell prints, I'm not a portrait or a wedding photographer, and reasonable accuracy is all I really need.
I'm wondering if, depending on the display, there's some compromise when trying to profile the entire gamut, and maybe that shows up in the grays. And if so, I'd rather favor neutral grays at the expense of gamut. If alternative software like DisplayCal gives better results or has more flexibility, I'll try it.