I've had several Kern Dagors, both single-coated and multi-coated. The latest MC version is unquestionably the highest contrast most hue-correct lens I've ever used in any format. That's understandable due to its only 4 air/glass interfaces. The contrast of the MC one proved just too high for most color transparency purposes. It's also a fairly heavy lens in a no. 3 shutter, though not as heavy and bulky as Commerical Ektars in even bigger shutters. I wouldn't use any of them on a lightweight 4x5 wooden folder due to their weight, with its risk of front standard vibration. Solid 8x10's are a different story.
The Nikon M's are ranked number two, in my opinion, when it comes to contrast, microtonal rendition, and hue purity - really good. And up to the 300 mm focal length at least, you have petite lightweight lenses usable on most lightweight wooden 4X5 folders.
But if you use the same 300M for 8X10 film, you have only a little wiggle room for view camera movements. Once you extend things towards the corners, the sharpness begins falling off. Head-on, or with just a little movement, the result is extremely sharp.
And indeed, the out of focus rendering of either of these lens designs - the Kern Dagor and Nikkor M - is rather harsh and clinical. Nevertheless, in the studio at least, using a blurry background fabric, the MC 14" Kern was my favorite 8X10 portrait lens with black and white film. These attained a cult status, so are tend to be very expensive now, whether they deserve that reputation or not. The
450 Nikkor M tends to be more affordable; and Fuji 420 L's are a real bargain, but again, relatively heavy.