I, too, bought one off of Onesaleaday.com a few months back: it's simply a USB-powered stand of sorts that has two mini-USB ports and is contoured to fit two PS3 controllers.
Is short, it's like gaining the ability to charge two controllers from the same USB port; otherwise, it's nothing special. And it certainly doesn't rectify the fact that the PS3 can only charge USB devices when its fully powered on.
I just have mine connected to one of my Wii's USB ports so that the controllers can be charging any time I set them in the cradle; and I do the same with wireless headset.
It's beyond rationale why SONY makes a trillions devices that require USB to charge, then strips their console down to two USB ports that aren't even active unless the machine is powered on. Somebody over there needs fired...