I've used the Dri-Clean from Blue Coral. I think it works very well as a general purpose cleaner (not so much for spots/stains). As you have only to either vacuum or brush out the residue once it dries, it is a good choice for someone who doesn't have an extractor or doesn't have the time/place to let a car dry out after using a "wet" carpet cleaner. The car can be driven sooner too (no unpleasant surprises for the driver). Also, there is less of a chance for the seat to be overwetted, so there is less of a chance of a stain caused by wet foam wicking. This would be, of course, a "Joe Six-pack" safety feature more than an Autopian concern. I think the foam dries a little quicker than the liquid spray version. A definite difference was seen when I used this stuff on a smoker's car interior-went from a "golden" to light grey. Very impressed owner (somewhat embarrassed also!).
Haven't tried the Power-Out.