I have tried N380 on my test electric bike, and i have bought two more of them since. They are a bit heavier then Shimano Nexus 8, i have heared they are a little bit less effective (some friction loss inside), but they compensate all those cons by the smooth shifting. It does really feel good and you can pedal with so much more comfort when you can set exactly how hard you want your gear to be.
The best aspect of this hub for an electric build is that it can shift both under and without torque applied. For a mid-motor it means you can forget about having it, when on a classic inner-gear hub it takes a bit longer for the controller to understand that you have stopped pedaling to disengage the motor so you can actually shift. On my non-electric bike, which is an alu Electra Rat Fink i ride in Barcelona it also feels great. The area is pretty hilly there and you get to cover a lot of distance when commuting by bicycle, so this hub performs great. Now i am also planning to change my Nexus 8 on my daily bike for Nuvinci.
The general advise is to get N380 instead. It is not such a noticable price difference (especially when you buy a used hub), but those 20% or 50% ratio difference you can really feel! Talking about an e-bike, N380 is also the strongest of them all, so no mid-motor can easily make it slip.
One thing you have to remember is that it runs 2 cables for shifting instead of one, and with a braking cable it makes 3. So you need to find a nice and elegant way to get 3 cables from your front end to the rear wheel of your bike, so it won't look and act like a mess.
So generally my experience about this hub is very positive, lets see what i'd say after a month or two of using it on my daily bike.
