Is Phantasm Good Terraria?

The phantasm however, has less damage potential, but generally does more damage. The Phantasm. You can rack up insane damage with it, especially combined with Holy Arrows. It shoots four arrows at a time, and the initial arrows that hit an enemy summon even more arrows.

Which is better Eventide or phantasm?

While Phantasm definitely has better dps, I'd argue that eventide w/ endless quiver is superior for events and mob encounters because of its straight line trajectory + piercing, and perhaps better for bosses for the same reason as well (less missed shots means more damage?).

Which is better phantasm or vortex beater?

Due to the inaccuracy of the bullets, the Vortex Beater is somewhat better suited against larger enemies and bosses (which may be immune to the knockback effect of the rockets, however). A better ranged weapon for single target damage would be the Phantasm.