When I had the NS strings on my NS DB, I found I had to be careful not to "dig in" too much, to prevent lots of rattling - since I put actual double bass strings on it (old set of Spirocores from my upright) and raised the action this is less of an issue.
Overall you have to bear in mind the scale length is a little shorter than a DB and be prepared to "tickle" it a bit rather than playing with the same energy you would with an upright.
The biggest pain is having to flick switches to play arco. I find the "combination" pick up setting not so good for pizz so I've somewhat resigned myself to this. I've never used the magnetic pick ups in anger.
I would say that whilst the playing experience is similar, the modifications in DB technique mean the NS is probably best suited to BG players looking for a way into the upright world, rather than those looking for an easily amplified, portable doghouse. As I've now realised I fall into the latter category, I'm seriously toying with getting something like an Eminence - when I can afford it!
