My CR Spotless Water System was delivered today. Looking forward to using it. It should make washing easier.
It really depends on the mineral content of your water supply. If your house has a whole house water softener this is redundant. If you run off a well then it's probably a necessity. It's a case by base decision.I never had an issue with water spots on my car. I would guess that all of us wipe our cars down. The products today used for waxing and detailing drastically reduce spotting. I think though getting the system you mention is great but is it really necessary.
I will likely use it along with a blower.I've had one for about 8 years and when the particulate is fresh they work great. The bad part, depending on how much you use it, is the replacement resin. About the best price I've found is around $50 for a DIC-10 and $90 for a DIC-20 (what I have). There are a number of threads on various detailing forums about using bulk resin and re-catalyzing (restoring) the stock resin but since I can get about 120 - 130 washes out of the DIC-20 I'm good for at least a year so I just suck up the cost. Mine has the particulate monitor so I know when the resin needs replacing.
Enjoy it but don't think it will completely eliminate the spots like the ads say, it just gives you more time to blow or wipe off the remaining water. However, the water that comes out of these systems works great with rinse-less systems and products.