I have used an Alfine 8 hub. I think they're reasonably well built and nice to use. And unlike the 11 speed version of the Alfine, the Alfine 8 has a gear that is direct drive (1:1). I always suggest setting up the gearing so that the direct drive gear is comfortable for cruising on the flat and gentle hills. That way you get single speed efficiency most of the time, and you only lose energy through the internal gears when you can't ride comfortably using the direct drive gear.
This gear calculator includes an Alfine 8 setting:
The bicycle gear calculator displays graphically the gearing of derailleur gears and gear hubs. It can be used to compare different setups to find the optimal gearing for all kinds of bicycles.
www.gear-calculator.com