>>1206811I've had Shimano levers outright fail, not due to a crash, but because one of the little gears inside go. It's rare, though, usually due to the grease inside of the levers getting old and gummed up. Mechanical STI levers also have a design flaw in which the cable gets worn out inside of the lever, and eventually snaps. Not a big deal if you keep on top of cable maintenance, but it can suck if it happens and bits of the cable get stuck inside of the shifting mechanism.
Campag Ergos are better in that they have less moving parts, so there's less in there to fail, but they still have a couple of bits that get worn and eventually make shifting suck. It's repairable but not something you want to do in the field. Newer ones also have tight cable routing inside of the shifters, and that means cable wear and breakage.
Dunno about SRAM. I'm sure they have their own quirks and failure points.
I think that the best touring bikes are also good SHTF bikes, so making them as durable and easily repairable as possible is a primary goal.
