I just removed the Darkglass from my Z2.5 and replaced it with the Nordstrand 3-band.
The Darkglass had a definite sound, and as much as that is a very cool sound - I really like the passive tone of my bass and I wanted something a bit more "true".
With the EQ knobs centered, the Nordstrand sounds almost identical to passive mode.
There is a slight brightness boost due to the buffer counteracting capacitive loading, but the basic EQ shape is the same, and there is a trim-pot to ensure that the volume levels between passive and active are consistent.
I still play the bass passive 75% of the time, but when it's time for a song that needs an EQ'ed sound, I just dial it in, hit the switch, and go.