I got mine and I've done one half-azz wash so far. It was getting dusky and I wanted to try it out...I ended up finishing it in the dark. Anyway, on to the thing everyone really wants to know about this thing: Do you need to towel dry?
You still have to hand scrub it with a soapy towel to get the dirt off though.
First you take this filter deal (they give you two "starter" ones to start with, each of which lasts about 3 washes, they promise the ones you buy thereafter will last much longer) and put it in the bottom of the unit. Then fill it up with their soap (they give you two bottles). The unit has 3 modes: Spray (just sends your hose water straight through at full pressure), Soap (mixes the water with soap and sprays it out at low pressure), and Autodry (sends the filtered water out in a flat sprinkeresque sheet). There is an On/Off switch as well which is convenient, but that means only one spray pressure, no variables short of turning the faucet down.
Once you're set up, spray the car down good, get the preliminary grime off. Then turn the switch to Soap, cover an area of the car with the soapy water (works well), then soap up your towel or sponge with it as well. Go to town on your car, when you're done, flip it back to spray to rinse off. Repeat for other areas of the car.
Once you're done scrubbing and soaping, flip the switch to autodry. Now here is where the trick is. The water comes out in a flat shape and is at medium pressure. You basically are trying to "blow off" all the standing unfiltered water on the car with the filtered water. Its a piece of cake on windows, the hood, side panels, and back. The only areas where its kinda hard to get rid of the standing water is on the roof and trunk, but that just takes a little time. Make sure you do this process from the roof down (otherwise if you wash the roof last, the unfiltered water will roll onto the rest of the car again and you'll have more work). Once you've sheeted off all the unfiltered water, your filtered water will sit on the car and evaporate away, leaving...NO SPOTS! If done properly, this will give you a waterspotless job.
Overall I'm satisfied, I haven't had a chance to use it again yet because its been really windy and has now been raining. But this definately makes washing much more streamline.