KMC have been making chains for many years and now produce over 80 million a year for a wide range of companies, including Shimano. The x10sl Gold sits at the top of their current road range, and as the name suggests is a 10-speed compatible chain (a nine-speed version is available, though).
Fitting is a doddle with the KMC missing link system (very similar to SRAMs powerlink in use) so for those of you who are very particular in your maintenance and cleaning removal and refitting is tool-free and simple.
The gold finish of the (blingin') x10sl is not only good looking but also has a titanium nitride coating, which is claimed to improve the wear. In use, the best thing about any chain is that you don't notice it, and that's exactly what I found with the KMC. It's as crisp shifting and smooth running as the Campag C10 it replaced, and after a couple of months' use it hasn't stretched or stiffened and still looks relatively good - not as pristine as it was as new, but that's to be expected.
The real bonus of the x10sl is the weight: at 243g out of the box it's light - very light - and once we'd removed nine or so links to get the length we required it was down to around the 226g mark. KMC have achieved this with the pared down profile and slotted plates (something Campag also do with the Ultra 10-speed chain) and hollow pins connecting everything together. The pleasing thing here is that this is achieved without the loss of strength or longevity, with the harsh weather and clumsy shifting of this tester not stressing it at all. We've looked around, and aside from the similarly priced Campag Ultra (which tips the scales at over 15g more), the only chain we've found that's lighter is the ultra bling and exclusive Connex Ti Chain (claimed 235g for 110 links) but that retails at over £220!
Price-wise KMC's x10sl is on the button, being about the same as Campagnolo's new Ultra chain (with a claimed weight of 259g), but a tenner more expensive than Shimano's Dura-Ace 7800 10-speed chain (259g 114 links). All in all, there's a lot to recommend here: it's good looking, hardwearing and has a lack of heft that will please all the weight weenies too.