howdy! i think i already had a nexus 8 at this point and i was curious about trying some other ones out just to see what was out there and what people thought.. i rode the nuvinci and a rohloff since then... still haven't found and imotion from SRAM. the rohloff was nice but i actually found my nexus 8 to have just as good if not better shifting (no where close to the same range as the rohloff, and 1/6th the price).. the nuvinci was cool, heavy, and for some reason i just don't trust it (probably not a good one).
the new alfine 11 has an oil bath lubrication system and a killer gear range, but costs 2 or 3 times more than the nexus 8...
i think nexus 8's are great and there is a bikeshop through the liberty tubes that kind of specializes in cleaning and maintenance for them (i've never been there, just met the owner a couple months ago by chance) that would probably help you put it together if you don't want to do it yourself (i'd also be happy to help you if you do want to do it yourself but you aren't quite sure about everything, its not quite like putting any other rear wheel on)