No I haven't. I've read about them on here, & they do seem to be a logical solution to an obvious design fault, but I'm always happy to hear comments from those who are more familiar with JMs than I am. I'm not really a trem user so that doesn't bother me much, but if it impacts on the tone, that's probably not a good thing. My JM is a Squier VM, & I have the action set up to my liking using the original bridge - the Mustang bridge is useless for me as it doesn't allow individual string height adjustment - a very strange omission. I don't have problems with buzz - I have the action on the bottom couple of strings higher than most people do to avoid buzz - as I do on Strats & Teles. I use 10-52s, & I'm not sure I want to move to 11s. So there isn't an urgent problem to solve. I just wonder whether the string slipping may become a problem if I use the guitar at a gig, which is only a potential problem at the moment. I think maybe it's best if I wait until it becomes a problem that really annoys me. As for the J. Mascis JM, I was warned off that a while back for several reasons. It has jumbo frets (I hate jumbo frets), it has a bridge with saddles that are not adjustable for height, I was told that the pickups are pretty hot (more like P90s), & I think I was told that the neck is quite fat. And I don't much like the look of it! So all those things together made me wonder why you said that it's "the only Jazzmaster really worth buying other than vintage or custom shop". Maybe for some people, but probably not for me. So "moving up" from my Squier VM JM is tricky. I don't want the Mascis, I was warned off the Japanese ones as apparently the pickups are just Strat pickups in a JM sized casing. Which leaves me with the Mexican JMs, & now you have warned me off those because of the pickups! Which leaves me with the AVRIs. Since I like the necks on the AVRI Strats, it seems logical that I would like these, but they're rare & hard to find & very expensive, even on eBay. A white one sold a couple of months ago for £1100 & a blue one (with different bridge & pickups) just sold for £1500! Which is why I have my Indonesian Squier. I would have no idea that it's Indonesian if I hadn't read the label on the back of the headstock, it's a nice guitar.