Official/FTL night: Its always dark. That's nights in my book.
300 hours. Doesn't sound a lot, but mostly in the infamous WOCL. See how that feels when day sleeping... Duty often close to or at limits allowable, rest getting closer and closer to min rest in many places. The flying's not the hard bit.
Not the worst job, nor the best. However, it is pretty much as secure as they come... Check out DPWN's (they own DHL) end of year reports.