i currently have a set of daedric armor with 28% destruction spell cost reduction on 4 pieces including the ring.
on the ring, i have the choice of

A
Fortify magicka + 70
fortify destruction -28%

or

B
enhanced healing rate +35%
fortify destruction -28%

for any mage/warrior build, which sounds better?

What other schools of Magic do you use? You're not spending any magicka on destruction spells since they're free right? If so, neither one would really help with Destruction at all, since you're always going to be magicka capped and all your spells cost 0.

How did you get -28%? Potions?