I bought the Warwick metal potiknobs to replace the ones on my guitar, as they were old and the screws were impossible to tighten.
I went for Warwick, as normally the W quality satisfied my needs
PROS:
Sturdy, nice piece of potiknob, well finished
CONS:
When tightening the screw, the potiknob loses parallelism with the guitar body, hence it gets an unpleasant "whirlpool" movement instead of a smooth linear one (note that I also changed pots, and the new pots had the right cut that theoretically fitted with the potiknob)
Every one in a while I have to re-tighten the screw, otherwise the potiknob gets loose.
Al in all, I decided to replace them with a different model.