Davey

Yeah, I have one. I have no shade to wash my car in so with a black car, when I first started washing it, I would have a water-spot covered MESS when I was done, and it would take me an hour or more with quick detailer to clean it up. I mean, it's usually half-dry by the time I can even get a towel out. Sometimes even the soapy water dries on the car while I'm doing the other side, if it's July and sunny.

So I got one of the CR Spotless setups. I use the cheapo Mr. Clean filter to fill the bucket (water is hard as hell) I use for soap and wash the car, and just try to keep it wet. Then rinse with the CR Spotless, I do a kind of half-assed job of drying it and it comes out great every time. Usually I go take it for a drive and come back and maybe I get a little bit of spots around things like door handles but it takes just a few minutes to clean up with Quick Detailer.

You could build such a system for quite a bit less than they sell it for, if you just made a simple filter, but it does have an indicator to let you know when the water isn't being effectively deionized and is engineered to restrict the flow to an appropriate amount given the amount of filtration material.

Anyway, I really like it. It took my Saturday car wash from a long frustrating experience to relatively trouble-free. I have rinsed the car and let it sit in full sun and had zero spots. If you very thoroughly rinse you won't even have spots after you drive it, but I don't mind detailing it a little when I'm done anyway, and I get a few more washes out of the cartridge before I have to refill it.