It is completely backward compatible with FFS, it's very fast and tough as nails. I don't know if it is even being developed any more. I haven't been able to get on the website for quite some time. Amiga should have tried to buy it or liscense it, instead of making what is probably a new incarnation of constant invalidations, checksum errors and repairs! :/
I really, really like PFS3 and hopefully the new OS will continue to function properly in the new OS. There are alot of people who use it
and don't want to give it up! :)