To elaborate on the title, I used these on a strat built to replace the other ones I had which came off a £120 guitar. Unlike the ones off the cheap guitar, these ones didn't rattle about, felt smooth to turn and have kept the guitar they're on perfectly in tune since installation.
The guitar they're on has a fixed bridge so I can't comment on how these hold up against some tremolo, but for the price, they're excellent quality.
I marked them down a star because the included screws were a pain to work with, the 3 that I didn't use either rounded out their head or just wouldn't screw in. For these I just used some other screws I had lying about.