Pros/Cons of each Marauder build

Drain won't save you when you're at a boss that does over 8k damage per hit. Even so, Barrage/Double Upper will outdamage it

You don't rely on drain to heal you at bosses, its for damage. I learned that the hard way trying to use it as heal at pianus. Barrage/double upper doesn't have range and doesn't outdmg drain for a while. Barrage does have that nice invincibility though.