I own all of these balls.

The Super Charge is my favorite.  It is a strong medium-heavy oil ball that lets me play the middle of the lanes (15-20).  It has a real smooth arching movement that works well for me as I like the control I get with it.  

The Power Charge Pearl is my fall back ball when the lanes are too dry to play the Super Charge anymore.  When this ball gets to the backend it has a similar reaction as the Super Charge but it gets down the lane longer before turning.  I'd call it a medium to light oil ball.

The Depth Charge has been tricky for me.  At first I thought this ball would replace my Power Charge Pearl, but it has a MUCH stronger backend snap which has given me some trouble.  After taking it out of my bag for a while I have recently started using it at a different house where they put the oil out a couple of feet longer than my normal shot.  This ball works great in that situation.

Summary:  Super Charge and Power Charge Pearl have a smooth, controllable arching movement to the pocket.  The Power Charge Pearl and the Depth Charge get down further than the Super Charge.  The Depth Charge has the strongest backend reaction.

Good Luck,

John