As with all HP drain items HQ's work better and more often. As a 60ish PLD I farmed lots of tigers in Battalia and Carpenters landing, A lot of times it only sucked back maybe 10 but that's b/c I was only missing 10. Rarely was I in yellow for hours on end and if I did manage to get that low it wasn't for long. Note I was using the Carnage Sword tho, not rapier. I doubt there's much dif between the 2 save dealy and mdg. For EXP PT it was totaly useless. Just a farming toay
Tested this rapier out a little in Qufim Island to see if I could get some information on how often this HP drain kicks in.
If I had to give it a percentage, i'd say you have about a 10% chance to drain HP from the target, at most it'll drain about 30 HP, at minimum maybe 10. I am RDM so I figured i'd test this sword out to help on some of my weaker solo.
If you're soloing using RDM/BLM, you don't need this Rapier, Drain will easily take the place of this sword. I have a Joyeuse I can use, so this sword was mainly as a play thing rather than sword i'd use all the time.
For other job classes, I can see this sword being of some use, especially for PLD which can help them conserve their MP pool for soloing. For RDMs out there, you can avoid this sword if you wanted, it may help a little if you solo using RDM/NIN so you could gain some HP back without killing your MP. For RDM/BLM, you don't need this sword, go for the most damaging sword you can, which at 55 is probably the Wise Wizard Anelace. Not to mention using an -En spell will completely overwrite the HP drain, losing you the -En spell DoT.
Hope this helps people curious about this sword.
Edit: Lowered the Percentage drain on this sword. Has a worse rate then I thought.