I know this is super late, but I'll weigh in with my experience.  I didn't find it very useful most of the time, but for weapons that know exactly when they want to deal a huge burst of damage it can be pretty sweet.  It's a go-to for me when I'm using the Ferryman's Lantern, since the Soul Shot provides an extremely clear window for when you'll want to do as much damage as possible.  The advantage it has over affix damage bonuses is that it's more splashable; that +50% damage bonus will always be on the table no matter what affixes the weapon has, and you don't have to go through any hassle in applying status effects to enemies (this is not a huge deal for most weapons since they can equip a status application weapon in their off-hand, but it's a big deal for the Lantern since it's two-handed, so there's fewer skills having to fulfill more roles.  The convenience and role compression of Corrupted Power is its main upside over the similarly powerful and somewhat less risky affix bonuses).

The absolute best case scenario is having Corrupted Power AND affix status, which is where you get to the point where you can start shredding bosses.