Unless they are undead, arcane spellcasters gain much more from the first one than the second. The options Arcane Inflicting grant are basically more ways of doing damage, of which at least wizards already have any number. Arcane Healing, on the other hand, lets you do things you cannot already do.

For fixed-list casters, i.e. beguilers and their ilk, I suppose this is added to their spell list and thus to the spells they can cast?