I have worn Danner boots throughout my career in law enforcement and my feet have always been happy wearing them.  Due to my current assignment, I wanted to try the Tachyon because of its light weight and sole construction.  I also purchased the Danner sole inserts and replaced the ones that came with the boots.  So far so good with these boots; very comfortable.  Couple of notes though:
If you are the type of person who ties their boots "tight", pick a different boot.  The upper are so thin, the laces will cause much discomfort to your shin and ankle areas while walking.  And, I have always ordered a size 10 for Danner and have always had a great fit.  These models, however, seem to run a little big (nothing that a thicker sock didn't take care of though).  I am not sure if its because of the lightweight construction or if the model just runs big.
Other than that, looking forward to my time on my feet covered with another pair of Danners!