The Good: Fits 9 speed cassette body Smooth shifting Lighter weight
The Bad: only goes up to 36 teeth not as compatible with expander ring upgrades (Oneup Wolf Tooth)
Picked up this cassette as part of a 10 speed conversion and have been pleasantly surprised with it. Shimano's SLX group set has gotten great praise overall, but personally I wasn't in love with their 9 speed group set that I was upgrade from, but due to an ordering error on my part the SLX cassette is what I ended up getting.
One thing I love is the compatibility with 9 speed cassette bodies. While we would all love 11 speeds, the whole switching of cassette hubs or getting new wheels, or even a new bike is a bit unattainable for many of us. My original cassette was a 9 speed Sram Power Glide and the Shimano 10 speed SLX slid right on with no problems.
Once the cassette was on things started out good, but then got rough. I was running into issues in the middle gears with the chain missing cogs entirely or shifting up instead of staying in place. After a little trial and error it turned out to be a slight tweek in the derailluer hanger was needed. After getting that squared the cassette worked great! Going up or down everything moved smoothly, no skipping or misses.
Only down sided I can find on this cassette is that the highest cog is 36. Would definitely like to have a choice of at least 40. Also since the SLX is a lower tier of Shimano components it doesn't come apart like you would in an XT or XTR cassette. This means it is not as compatible with expander cogs like Oneup and Wolf Tooth. With the SLX cassette you will have to do some cutting to make an expander work, so if you're interested in doing that be aware.
Overall a great cassette and I have been happy so far. Only have had one for a couple of months so we will see what time will tell.