I have two, 12-speed Micro Spline 10-50s on different bikes. I wrote ZTTO for a long time asking when they were going to sell this lightweight version with MS splines. I have been using my first one for about 1.5 years and it has held up great. I purchased the second one about 6 months ago, and it is on a bike I don't ride as often. (My first cassette was probably from the first batch they manufactured. - They wrote me that I was the first person they were notifying that they were now available. so I purchased one right away.)
As a side note, 3 of my other 12 speed cassettes are XT micro-spline. I can't tell any difference in how the ZTTO shifts versus the XTs. I am also using The Wheel Top EDS OX on 3 of the 4 bike I run 12 speed. (Soon to be all 4)
I have 7 rear wheels with 12 speed cassettes. 3 wheels run a XT cassette, 2 are ZTTO the cassette you asked about, and 2 have ZTTOs slightly heavier version. 2 bikes are Super-Boost, and the other 2 are boost.
well I'm pleased, you are an excellent tester!
I'm thinking about what gear to buy, I saw that Shimano makes 10-51 while the Ztto ones are 10-50 or 10-52. if you notice the difference in the teeth it is all on the last 3 largest sprockets. shimano gradually increases the number of teeth but until the penultimate 42 they are both the same then it jumps to 50 or 52.
I would prefer 10-52 to have a greater range of gears but the fact that between 42 and 52 there is a jump of 10 teeth stops me, isn't that too much?