Massive thumbs up. The Eagle XX1 bling gold drivetrain is possibly the most expensive available. Yes you can now get the 500% gear range from the GX version that comes in complete form for £425 rrp. BUT it turns out that, that gold chain and cassette are hard as nails and after 750 hard miles on my Yeti SB5.5 it still looks practically like new. A parktool chain measurer clips in to the chain and and supports itself set on Zero (yes after 750mile) pretty amazing. Also the gold finish on the chain is very much still in tact and the cassette, showing very little signs or wear at all. I do keep it clean and only ever use the wonderful Squirt Lube which I think has made a big difference also. So yes its uber expensive but if it last 2, 3, 4 times longer does it start to pay for itself?? Time will tell ;-) cheers Sam