I bought this to give me a little more gear on the 20% climbs in my area. I had been using an 1132 on my Ultegra 6850 equipped Roubaix. It did what I wanted, with the added benefit that it fits my old 10 speed wheels. The carrier for the largest gears is concave so it will fit the slightly shorter 10 speed freehub body. You need to use a spacer for 11 speed hubs. On the down side, it's 45 grams heavier than the 1132. It works fine with the medium cage Ultegra derailleur.
Top quality Shimano cassette, this cassette is about an ounce lighter than a sram one for the same gear range and shifts a bit smoother on my one by cross bike. The extra low end is a plus on some of the steeper cross crusade courses like ninkrossie.