The short version is that I think it's much more stable than many people give it credit for, but not so stable as we'd ideally prefer. But sweeping generalizations can be misleading - the details of how it's processed, displayed and stored are very important. I now tone all of my RC "keepers" with selenium. I don't mind, because the extra process step is not too much of a burden with RC, and because for my taste most RC emulsions look better with light to moderate selenium toning anyway.
Originally Posted by miha
I suspect the biggest long-term issue is the inherent stability of the PE layer and its adherence to the paper base, under long-term display or storage in environments that are poorly controlled for temperature and humidity - which is to say, the kind of environment where most of our prints will end up if they're saved at all.
It should be noted that the long-term stability of current FB papers is also an open question. We know almost nothing about the characteristics of the paper that is used, and whether and in what ways it has changed from papers used in the past. Long-term survival of prints made on FB papers many years ago may not tell us much about the stability of FB papers manufactured today.