Ronen Sarigwrote a review of Shimano XT Dyna-Sys CS-M771 Cassette on March 12, 2015
Familiarity: I've put it through the wringer
works awesomely, until it breaks. I rode it pretty hard for 2+ years, until the alum arms for the larger chainrings sheared and broke. just ordered another.
something to note: these later models (2014+) fixed an issue that the earlier (circa 2012) models had: the older model's small cassette chainrings had narrow profiles with spacers between the rings. Since the interface between the chainrings and freehub body was as narrow as the chainring teeth themselves, if you pedaled hard, the chainring would cut into (and mar) aluminum freehub bodies. The newer models have the spacers between small rings integrated into the rings themselves, thus increasing the interface area between ring and freehub body, and reducing the marring of the freehub body.