Hella amount of people like the Duals much better, the reason being "ALL THE BULLETS!" But without any Formas, shot-for-shot, Vasto is better with that "V" slot. Put a high level Hornet Strike on and two bullets from the Duals will equal one or less of the single version. All that aside, Duals have better DPS because BBBBBBBBBBBAM. I like the Vasto better, most like the Duals.