The Das Keyboard is my home keyboard and is just an absolute joy to use. It feels like an IBM Selectric typewriter from the 1960's. With the o-rings, it is not that loud. The switches click, but the keys never bottom out. I did not like the all black switches so I changed them out with a set that looks like a model M.
The Unicomp is my work keyboard. It feels like the keys travel further before activating, but I do not know if that is real or just a perception that I have. I work in the mechanical piping business and the Unicomp is more suited to the abuse that it may see in my world. It would not be unheard of for me to get grease, liquids, or metal shavings in the keyboard. I just cannot bring myself to use a keyboard with Cherry switches in that environment. The buckling spring keyboard is virtually impervious to such problems.
So, I cannot recommend one over the other. I use them both and like them both. I suppose that with everything else, what you get is a tradeoff of the desired attributes.