They're both good procs but honestly I think Magic Missile after buff might be a bit better.
MAGIC MISSILES:
Damage and Mana cost increased by 20%, improved targeting
Now starts at 4 projectiles up from 2. Additional projectiles now gained every 5 levels, up from 3
Base explosion radius doubled
Meaning 14 total missiles hitting with increased AoE.
Balefire is the same as before, nothing changed. It would be amazing if you could have Bacchanalia with it but you can't.