I'll just say that even in sRGB displays, both of those brands were better than Apple, and it has nothing to do with image bit depth. Even gamut is overstated. I mean you're looking at things in gamma encoded profiles as it provides a means of displaying an aesthetically pleasing image over a limited dynamic range. I think you already knew 16 bits vs 8 bits had nothing to do with your point

.
My opinion would be if the OP is looking at an imac, make sure to use one of the more recent colorimeters, or a spectrophotometer works too if he owns one for print measurements. I'd just avoid the colormunki design spectrophotometer, not to be confused with the colormunki display. If he's using it for still images, test it to see how prints match. I don't do much of this stuff anymore, but I can say the display makes things a lot easier when you're trying to fine tune one color relative to another. It's not like you can measure absolutely everything.