Do it mate, I got an SSD a few weeks back and my GOD FFXIV runs so smooth and fast now, almost no load times
Make sure its 5400RPM though or you'll over heat the PS3 and kill the machine, 7200 might be a few seconds faster but the PS3 wasnt built to cope with the extra heat they emit.

EDIT: example since I timed it, it took 1min from log-in screen (user name/password) to get to the adventure field (New Gridania) during UK Prime Time the other weekend