Is there any appreciable difference between the deore xt rear derailleur m760 (last year's model?) and the m770 (this year's model)? If I can get a new m760 for $50, is it a better deal than a new m770 for $75?
If it's the new shadow design it's completely different. As mentioned, it doesn't stick out as far (there's not a point on the RD that sticks out past the QR skewer) and as well, the shifting feels different- a little more like SRAM, a little faster and rougher. I like it.