Re:
i guess durable and sweet shifting do not go together, i have had a xtr chain on a rig for 2 years but i ran it into the ground - in the end the big ring cracked and i had to replace EVERYTHING. but shifting was always faultless. ive had one kmc x9sl gold (?) it did not shift great for me but was light.
ive now gone for changing the chain more often to keep the rings and cassette nicer, but im now running deore chains, the shiftings good on them too, it is heavy and higher maintenance though.