Magic Missile is life. It's probably one of the few 1st level spells you'd actually still USE on a regular basis.
Arcane Bolt, on the other hand, allows a saving throw, a major strike against it, as it automatically cuts its damage in half outright, because enemies never fail saving throws, and against enemies with evasion or improved evasion, it's beyond useless.
MM, however, is the ongoing plague of the reflex-enhanced, right up there with Acid Arrow, which will inflict a total of 14d4 in painful acid burning at max, which also has no save. No save is good.