how can anyone really ask how this is differnt? it is an EXTRA boost in hp. you get hp from the level, but when you get this trait, it is as if you gained another level in hp.. so instead of 15 or 20 hp, you get 50. if you get 30 hp 5 times, that is 150 extra life, but each hp boost is more than the last.
(not sure exactly the amounts)
but say hp boost 1 = 30 hp, 2=60 hp, 3=90 hp, 4=120 hp, 5=150 hp, add that all together, and the boosts give you an extra 450 hp (that really helps at the end if you ask me)