I'd agree with Mal that RK seem to have lost it a little lately. Maybe the importers are just not bringing in the pukka stuff, but the last two RK's I had didn;t last all that well. A good DID, EK or Tsubaki (If you can find one) will all aork noice! Just get the top of the wasser in whatever you get, it's worth the investment. I've got a chain on atm which will see 5k before it's knackered. I've been adjusting it every fuel stop! Oh...it's an RK too!
I got EK and AFAM sprocket kit from a reseller that gets them from Ron Angel Wholesale, lifetime warranty on the sprockets, just buy their chains for life, and use standard gearing.