I've run a NW ring on my commuter / winter bike for 3+ years and dropped my chain maybe three times. Non-clutch Campag Veloce mech. Run a NW on the HC bike and never dropped a chain, though it's in tension pretty much 100% of the time.
Yeah, I run a CeramicSpeed jockey cage though which is very light tension and I'm it's when I'm in the 11, 12, 13 that I've thrown chains in races. 10s and 25 milers so maybe not as likely in a 12hr but I'm still trying to do 25mph so there's some faster bits where I'd be in the smaller cogs.
I've run a NW ring on my commuter / winter bike for 3+ years and dropped my chain maybe three times. Non-clutch Campag Veloce mech. Run a NW on the HC bike and never dropped a chain, though it's in tension pretty much 100% of the time.