Samus has 10 missiles. Anything more damaging and it would be a big spam problem. Shoot super missiles instead for bigger damage... seriously, most projectile classes except for dante, meower AND samus, have reloading issues after prolonged spamming. Samus always has a weapon to fallback on, whether you use the charge shot after 2 super missiles, or go into morphbomb mode to lay down some bombs. She can fire her M1 while reloading rockets.
The Vault Boy's best weapons (both melee and ranged) are supposed to be extremely good. Possibly the best ranged and best melee weapon in the game.
In fact, I lost like 9 out of 10 melee only rounds versus Fish with the super sledge.

The author stated that the weapon is extremely effective against characters like Dante (whom it can kill in two shots), Bo Jackson, and E. Honda.
However, since stats are totally random, you could get stuck with bad other stats. Low charisma means you cannot hang around your teammates too long. Low agility means slow speed and low ammunition (although 4 shots with Gauss Rifle is more than enough to kill most classes). Low endurance is very, very bad when fighting super strong guys (everyone).