I have new black ULT and old ULT from ZTTO and both are solid. There are quite noisy especially with shimano chains. I did 10k km on the old one and it started creaking so I ordered a new version but when I swapped them it turned out that bolts connecting two clusters got loose so I tightened them and I still use it on my spare bike. On the new ult there are rivets instead of the bolts so will see if it holds up. I had 9-42 ztto xd cassette on my gravel bike and those rivets started creaking after about 6k km