I am just about done building up an old 80s Peugeot MTB around one of these hubs (the "red line" hub, not the Alfine). Conditions here are wet and gritty much of the year, so I seem to go through cassettes and chains like nobody's business. I am hoping to recoup some time there.
The results so far are good, but I don't have my handlebars yet so I can't report how it rides. It certainly is easy to build a wheel with one of those hubs though, and the look is exceptionally clean.