I've been dealing in the Alfine hubs for as long as they have been on the market. I was operating a bike shop when they first came out, and one of the bike brands I handled, Brodie, was one of the first OEMs to offer a Alfine equipped bike.
I sold out of those bikes each year, and did about an equal number of after market retrofits.
Even with the early, 500 series hubs, there were very few issues, and when they did crop up, it was always shift cable related. Either too many tight bends, or the cable not routed correctly around the cassette joint capstan, or just a matter of the adjustment being off.
I'm not discounting the fact that some have had issues other than those, but I've seen very little of that over the rather large number of these hubs I've sold and serviced.
Until this year, I never had one of these hubs in a bike of my own, but I recently built up a commuter with an Alfine 501 model.
I will post more about this bike soon.