I'm really digging SRAM stuff lately. I have 2 sets of wheels. On one, I have an XT cassette, on the other I have a SRAM 970 cassette. I have been running a 990 chain on either cassette and it seems to work equally well.

I totally prefer the SRAM chain to my XT chain that I usually use because of the power link. It's so easy to take that sucker off and give it a thorough cleaning every blue moon.