Das is a popular more popular brand for mechanical keyboard enthusiast. Most enthusiasts prefer mech keyboards with Costar stabilizers for the longer keys that sit on one switch... so they don't rock or feel mushy. The only keyboards I'm aware of that have Costar stabilizers are in Das, WASD, Filco, Rosewill... and I think Blackwidows have them. However, I'm not a fan of cherry black switches. I like my mechs with clicky sound. I would rather go with cherry brown switches if you don't want the clicky sound. At least cherry browns have the same tactile feel as my blue switches.
Not sure on the logitech if it has Costar stabilizers... and I'm not sure what switches it has. Between the 2, I would go with Das... but I recommend going with either brown or blue switches instead... unless noise is an issue in your house.
EDIT: I guess the Das doesn't have black keys... I mis-read black USB as black keys. Looks like it has gold-plated, mechanical key switches. I believe those do have a clicky sound to it... my preference between the 2 choices is still the Das keyboard.