Perhaps I'm a bit off the wall, but I usually use a shimano chain with a sram link (makes it sooo… easy to take the chain off for cleaning), I prefer the shifting of a shimano chain when new, but to be honest once they're caked with quantock grinding paste they all feel the same.
That said, I think there's probably a mix of makes across the fleet at the moment.
Use the same chains on 7 and 8 speed, no probs – but tried an 8 speed on a 9 block once, not good :?