Dark Woolite and Dark Cheer: But Do They Work?

Okay, so I use Dark Woolite and Dark Cheer when I do laundry (which I'm actually doing now, at 1 in the morning, because I'm a freak). It's supposed to be better for my dark clothing which is, of course, all I wear.

But does it actually work? I ask because, honestly, I can't tell. If anybody has an opinion, go ahead and comment.