I've been using a CR4 for a few years now, in a variety of settings. I am very happy with the sound - many of the same characteristics as an acoustic. The only difference is that the notes don't warm up the way an acoustic does as the wood vibrates, and that is more obvious in a setting like a trio or quartet. For larger ensembles, and certainly for a big band setting, it is truly great. And certainly very passable as an acoustic substitute in the smaller groups.
I blend the two pickups, and that seems to give me the sound I want, and of course I use Thomastik acoustic bass strings, not the strings that come stock on the instrument or electric bass strings.
If you do get one, watch out when you play in the high register. If you keep your thumb behind the neck as you go up above the octave, you will get a repetitive strain injury. On an acoustic, you are forced into thumb position by the bout of the bass - not so on the NS, and a painful injury can result if you don't consciously move into thumb position just as you would on an acoustic.
Rick