The V2 were alright. I'm typing on them on my NCR-80 right now.
They were affordable, so I bought multiple pairs.
Some issues - the larger stabilized keys wobble slightly when touched, the smaller ones minutely-so. They are straight when idle. They don't rattle. Overall, I'm happy with their performance, they don't seem to be much of a factor, positive or negative, in typing.
My spacebar uses those pre-tooled Cherry stabilizers that used to be affordable. It is completely straight. No wobble, no noise when not depressed. It's using a CRP 7U spacebar, and is basically a demonstration of straight spacebar.
Had an issue with the C3 V2 stabilizers on my KBD67 Lite. I was pulling out a keycap on an MX Clear that was a stabilized key, and the stabilizer insert broke off. Might have happened with a second stabilizer as well. Now, PBT keycaps can become very affixed to new MX Clear stems, so it wasn't a typical situation. KBD67L is hotswap, so it was an easy fix. But I am very careful with C3 stabilizers around MX Clears now. [I think they're fine for the average board that isn't hotswap and doesn't use tight stems.]