Who knows about Shimano XT and XTR cassettes?
I have a vintage GT Xizang (titanium frame) mountain bike, with XTR throughout. In shopping for a new cassette for a second set of wheels (with Marathon Plus tires for touring and utility use) I'm considering XTR M960 vs. M975 vs. XT cassettes. Big price shifts!
I want not only light, but super-durable. And maybe consistency in staying upper-end Shimano components is an ego thing, I don't know.
What would you do? How much real difference is there?