I'm coming up to a drivetrain replacement. I usually use a £10 chain for winter duties as they get so abused. But what about these expensive KMC chains? are they worth it? has anyone ran one and do they last longer and therefore reduce the amount of times you need to replace the cassette and chainring?

I've run top end SRAM chains PC 991 hollowpin and it was no better than a 971. Still rusted and snapped early. Stretched as quickly too.

I've not found that expensive chains last any longer, they are just lighter.
I usually go mid range.

I use connex wipperman, it lasted a full year , I replaced it with the same and it saved my cassette and chainrings.

i'm impressed with xtr/dura ace 9speed. did stretch but much better than the replacement budget sram.

buy lots of cheap ones and replace them regularly, you should then avoid replacing cassettes and rings

IME slightly more expensive chains are easier to keep clean, and won't rust up if left wet overnight, whereas a cheaper chain does. It'll still rust if you're careless.

I rather like KMC X9.93 ones, not too pricey either

Same as Hal – very impressed with Wippermann 908 chains; they come with a their own version of SRAM's Powerlink.

I notice very little difference between the cheap sram 951 and the 991. It mostly comes down to cosmetics. The 991 is easier to clean but that only the superficial outside of the chain lonks not where it matters (I've never dismantled one to find out if it was any cleaner).

As for weight the gains are pitiful unless you are spending lots of money and have already looked everywhere else to save weight first.

I use cheap shimano and sram on by hardtail. 991 on my full suss and road bike (for vanity).

I use connex wipperman, it lasted a full year , I replaced it with the same and it saved my cassette and chainrings.

+1

very impressed with Wippermann 908 chains; they come with a their own version of SRAM's Powerlink.

+1 again. Except the quick link on connex chains is much much better then that sram thing.

KMC X9.93 for me.
X9SL is great becasuse its so light, but thats the only advantage over the cheaper one.

i like the nickel plated kmc ones, they last me ages and don't go rusty

+1 for the nickel plated KMC been running one for 2 months 450 miles and it still looks almost brand new and hasnt stretched

If you lube a cheep chain it wont rust 8)

I'm using a KMC x9 and I've been using Finish Line wet (cos that's all I had with me) and it got surface rust overnight. My 9SL with gold / ti whatever coating has never done that.

Just bought some FL Dry Teflon stuff and stuck that on. Will see how the chain looks tomorrow. More than likely the wet lube washed off as it peed it down overnight. tbh.

I'm pretty impressed with the 9SL chain really. You can get them for a little over 25 quid on ebay too.