FWIW, I've ridden my Nexus-7 based Nishiki now for four years. I don't have an exact mileage, but a few thousand kilometers is a minimum I've ridden with it. Mainly commuting, but some longer trips as well.

Due to my commute, I ride it on pavement, on gravel, in mud, in wet conditions and occasionally during below 0 degrees centigrade.

I have to park the bike outside in the pouring rain, sometimes for weeks (of course I ride on it daily, but it stays in the rain, when I go in).

Sure, some of the metal parts are slightly rusted on the sprockets of my bar and brakes...

... but the Nexus-7 keeps on going with only two lubes during the whole time.

No misalignment, lost gears, odd sounds or any maintenance.

It just works. Day in, day out.

I'm not a hardcore drive in the snow type of a biker, but I'm not the scared of rain type either.

For me, coming from a series of derailers - this thing is exactly what I wanted: simple, relatively maintenance free compared to derailers I've used (nothing is absolutely maintenance free) and just works.

Now, maybe it's just my unit and maybe I'm in luck, but I'm going to risk my luck and the next bike I'll get (when this one is beyond repair) is going to have a hub gears in it as well.

YMMV.

cheers,
halcyon