Yes, me personally. Last year the XT freehub on my LHT suddenly and dangerously failed to the point where it was totally useless, though luckily I was near enough to my house when this occurred. There were symptoms leading up to this that I didn't identify at the time, mostly something similar to intermittent chain suck from the cassette when I'd stop pedaling, but I didn't realize it was a part inside the freehub itself that was causing this.

When it finally failed it essentially became a fixed gear ...except for when the pedals would slip a few revolutions without engaging anything at all. Totally unrideable. A lot of times when a freehub quits catching you can shoot some solvent into it to free up the gunk and get it working again (at least for a while), but in the XT's case the internal mechanism was literally smashed to smithereens. Once I got the super-fragile seal off the end covering the bearings little bits of metal shards came out.

Now that's bad enough just pedaling around town, but on a bike tour should something break, IMO, it's important to have the part be easily serviceable with readily available parts, which the XT FH-M770 was not due largely to the 14mm axle. I called around and most shops would have had to order parts to fix it whereas they all would have had me up and running with virtually any other commonly available Shimano hub. This was in a good-sized city, I have no idea about shops in smaller towns, but chances are I'd have been waiting around for a while...

Many, probably most people will ride this hub with zero problems, but I don't trust it any more and can't recommend it as a reliable component.