ggunn said:
It's like anything else - it's a tool that one needs to understand in order to use effectively.
With no disrespect, I understand them perfectly. I know all about the so-called "fixes" to make them stay in tune less badly.
They will
always have tuning problems, which means that
all other things being equal, they will
always be harder to get in tune and harder to keep in tune compared to a solid stopbar tailpiece, for reasons that are obvious to any engineer or reasonably bright layman. You described the exact main (though not only) problem with them when you said what happens when you break a string. That's just the grossest manifestation of the basic problem that's going on all the time you play.
If you don't believe me, ask Dan Erlewine or other legitimate guitar maintenace guru, and you should see the rigmarole he goes through to get a vintage-style Fender vibrato set up for minimum tuning problems, which he admits will never be fully eliminated because of the very nature of the device.
When people say they have gang-strung, floating vibratos that don't have tuning problems, what they mean is that they don't notice them or can live with them, or they're not as bad after tweaking the setup. The tuning problems
will show up on a good tuner.