Id say SFS is the better of the two since pfs wastes so much space on the hd, (10 megs for every 100 alocated as i recall). Also sfs seems to slow to a snails pace when a partition has lots of small files (like a browser cache). SFS however is still developed, if a little slowly
Personaly i havent found the need to move from FFS(and yes i have triedd the alternatives), theres little to no difference speedwise on the crappy builtin ide port and my 040. Since the os39 updates, validation hasnt been an issue. the pros for FFS are 100% amiga compatable and working recovery tools(wel upto a point anyway).
The FFS setup is a little different under os35/39 which is where it gets its speed boost (bigger blocks and correct maxtrransfer setting for amiga internal ide).