The addition of a massive 36 tooth cog is one of the key features of Shimano's new 10 speed Dyna-Sys range of drive trains. The big advantage to the 36 tooth cassette is that you'll be able to stay in your middle and big rings longer meaning that you'll ultimately be shifting less. Who would have ever thought more gears would equal less shifting.
My 29'er has a full XT drivetrain, but when it came time to replace the worn 2x10 drivetrain (which happily lasted a whole season of muddy rain rides), I opted for this SLX cassette due to it being slightly cheaper. Performance wise, there is minimal weight penalty. It's also good that I can get this cassette in the same gear range as my old XT cassette. As far as shifting quality, I cannot tell any difference whatsoever compared to my old XT cassette. To-date, I have competed in two different races with this cassette and feel at no disadvantage to someone even rockin' full 10spd XTR drivetrain! All-in-all, if you're riding 10spd mountain and are someone like me who will replace their drivetrain frequently, buying the SLX is surely a good way to save money over the pricier XT. 5/5 stars.
the 36t is awesome on my 2x10 29er. saviour on the uphill.
Good set of gears, can't find anything wrong with them, and good on the wallet as well