It's due a replacement relatively soon, but the tireless durability of this mid-level lump demands a lifetime service award. The bigger rubber external seals protect the internal ones and even sets we've run for years contain unsullied green grease inside.
Unlike most hubs, the bearings are the old fashioned, user adjustable 'cup and cone' type rather than disposable cartridge bearing versions. With a bit of servicing, lifespans are almost indefinite even in the worst conditions. The chunky body and silent running steel freehub are tough enough to take even jump duty, too. Complete Deore based M:Wheel sets are also available.
On the downside they are particularly heavy, which might frighten off race types, and they're QR only, but otherwise they're impossible to fault for the money. New XT hubs look set to deliver the same superb longevity in a much lighter format, too, but unfortunately they weren't ready in time for us to be able to do anything more than initial testing. Watch this space, though.