Are they as durable as their 8-speed cousins? Based on recent experience with a SRAM PC49, I'm guessing not due to the thinner construction. A slight jump now and again from the gears on the road bike over the past few days was, I assumed, due to a slightly worn chain. Not to worry, I thought - I'll buy a new one at the weekend, problem solved. Rather more serious than that, it turns out - on close inspection, an outer link plate had started to split around the pin-hole. Seems I've been very lucky, having ridden it in that state for about a week over some fairly tough hills without it giving way!!
It's also the only time in 16 years of buying and using them that a SRAM/Sachs chain has let me down. Plumped for the more expensive but apparently sturdier Wippermann Connex 900 as a replacement, so I'll see how I get on with that.
Probably the original Campag 10sp chains that Rob had in mind - I remember them getting mixed reviews in the early days due to the Achilles heel around the joining point. I also seem to recall that they couldn't be split and re-installed once fitted, making servicing either an awkward (if the chain stayed on the bike for cleaning) or expensive (if you binned it for a new chain) business.
My own broken 9sp chain was a different kettle of fish - it fractured many links away from the Powerlink section itself.
I've used SRAM 9-speed chains for years with no problem at all, despite my well-known aversion to cleaning bikes in winter. 951/971/991 all work fine, just have different degrees of shininess. The Powerlink system works well and I've never had any trouble getting them either on or off.
Never had any problems with chains - either 8's, 9's or 10's & only ever had one snap on a club run in 1993!
I've always rated 9's for their durability and cheapness!
Then again I never leave them on long enough to cause a problem - I've always treated them as disposable as its a false economy to leave them on too long as you will be replacing your cassette aswell or worse the thing will snap. On my race bike I will put a new chain on in Feb and change it again mid season. A good wear indicater is if you can lift a link clear of the chainring teeth, its knackered! Its worth taking the time to make sure a new chain is properly joined. I never ever take a chain off to clean it - you just risk weakening it. Remember to keep it well lubed even if you don't clean it often.
New Wippermann chain arrived from Wiggle today - one of their more basic products (no stainless steel bits or shiny nickel-plating) but on first appearances, build quality looks v. good. All that remains is to actually fit it to the bike!