in allocating stats, 3 important points should be considered if you want to specialize in:
1. pvp or dungeon
2. attacks or skills
3. type of char
so allocation still depends on these..
vandreadjura is correct, as the card description says, there's a chance (the percentage chance isnt mentioned,its pretty low like 3% maybe) to gain x% of your damage as hp.. for my case, i prioritize def over vit to take advantage of my hp gain (*wink)..
mp gain on the other hand always take effect and does not depend on your damage since mp is not quantified (my theory is that every normal attack has specific set amount of %mp gain :Þ) therefore if you have 50% mp gain for example and you hit with a combo that normally gives you 2mp bars, you will gain 3mp bars instead..