in my opinion mids is shit that wasnt taken care of during its life, for example planted in masses and not kept free of males and pollen, then when harvested it was abused and not handled gently thus knocking off more trichomes. and then when bagged it was brick packed to ship more weight.
kind bud (what i call it) can be from the same gene pool but it was just taken care of. (not many seeds at all, still trichomes left on it, and in bud form not pancake)
from my experience you can take a mids seed, mostly ones that gives you a decent buzz, and plant that seed. (no they dont dry out and die with the bud) I have gotten some of the best smoke ive ever had from a random bagseed. its all about the genetics, not how the bud was handled during the clipping and shipping process.
so overall in my opinion the dif between mids and kb is the handling of it. but purebred shit and stuff with names like white widow etc. is on a different level.