I've had in the neighborhood of a hundred fail in servers at work. With two models (different manufacturers) a large number of drives failed within the first weeks of use. The other model fails randomly in our systems with raid controllers and sas expanders, possibly connected to a firmware issue on the ssds. In any case, the failure mode is the same -- the disk disappears from the bus, never to be seen again. The failure rate is much less than when we ran similar number of conventional hard drives, but the failure mode is much worse. We don't have a particularly high write rate, so none of the failures were connected to media wearout (to my knowledge)