Nicca cameras are pretty good representations of the Leica Barnack cameras. I owned both in the past. The Leica seemed to have been built a little better, but both are very similar in size and style. Both suffer from the same flaw, duel squinty windows. I never seemed to have my eye to the right finder that I needed it to be, rangefinder to focus or viewfinder to compose. I settled on a Canon IVsb2 which is every bit as well made as any other camera of it's era, though just slightly (just a sliver really) larger, and not as stylish. But it has a single RF/VF window which is larger than the Barnacks prior to the IIIg and any copy.
I will guess that all of these cameras can be serviced by the same technicians. I have no idea the value of Niccas these days, the market is crazy. I would guess though that the value is not greatly different than that of a IIIf, and that it will be easier to find a IIIf if you choose to pass on the Nicca you have already looked at.