both are good, there are advantages to both. The sram is already locked out The cable doesnt loop around the back but they are heavier The frame bolt is alloy and non replacable the cable guide around the rear is plastic and gets damaged they are ugly The shimano xtr is lighter Doesnt have a cable adjuster on the rear to snap off. the frame bolt is easily replacable you can get it in reverse pull (BIG plus in my books) better looking. But they dont come with really short arms, so you have to mod it. They hit the chainstays if not locked out and the might be a bit weaker than a sram cant go wrong with either really, but I use shimano as they come with reverse pull which I like.