Sachs-Sedis [now owned by SRAM] invested a lot of time, money and research into their chain design, both for shifting and pin strength. The higher-end chains have better riveting processes which lead to lower failure rates. I'm still using a Sachs chain that I bought in the mid-90's that is on its third bike. Granted, the chain went from mtn to road to singlespeed, but damn! That's way more life than I ever got out of an XT chain. The Power Link kicks a great deal of ass as well.