Quick update for everyone eyeing these cassettes:
I've been riding two of these for the last 6 months.
I ordered an 11sp 11-32 cassette with grey finish that I used on my steel roadie with Campagnolo Chorus. It has been flawless. No issues. Being a one piece unit, it transfers more noise to deep carbon wheelsets. So your drivetrain can seem noisier at times, if that concerns you.
On my VB 218 I put on another one of these, this time a 12sp 11-32 cassette. They only had it in stock in rainbow finish. I ordered it regardless. Again, it's very well finished. BUT after just two rides it developed a creaking sound. I narrowed it down to the black aluminium spider that the steel cogs are riveted to. There is some slight play in there, so you can rock it slightly back and forth on the spider. So particularly on the big cogs of the cassette under high torque (i.e. when climbing) I got a very loud creaking. It probably doesn't affect the functionality. Time will tell how durable the thing is.
I took the cassette off, cleaned it and put some Loctite on all the riveted interface areas between the spider and the cogs. I let it dry for a night and did another ride yesterday. Now it's quiet. Let's see for how long.
You could probably also just grease it every now and then. But I'm using wax on my drivetrain and didn't want to introduce oil or grease to my drivetrain.