An excellent cassette for the price, the SRAM PG-990 cassette provides excellent shifting with cogs that are ramped and machined at strategic points for great shifting under all conditions. A CNC-Machined alloy 5-arm spider supports the largest cogs, stiffening up shifting while also saving on weight. The splines fit all Shimano compatible freehub bodies.
The PG-990 cassette has been my go-to cassette for years now as it has such snappy shifts when paired with the 991 CrossStep chain. It seems super well machined and gets the job done just right every time. I generally find that I run my chains a little longer than I should as far as wear goes so whenever throwing on a new chain causes odd sounds to come from the rear I just throw on a new 990 cassette and unless I've trashed the front chainrings it usually just works great after those two things.