I have used the California Water Blade, 15 years old, basically for 15 years now, and have not noticed any significant damage from it. That doesn't mean I don't worry, though. After seeing videos on You tube with people using electric leaf blowers to dry their cars quickly and completely, with the water out of all the crevices, that is what I am going to use from now on. I have been using the water blade because it is really quick, and I haven't had any quality towels handy. I have been using the blade to get most of the water off, with one pass per section only, otherwise it will squeak, and increase the chance of marring. Then I use a towel to remove the rest. I still have water left in the nooks and crannies, though, which drips out for the next 30 minutes. I have to say though, that I always wash a car TWICE, once lightly to get most of the big grit off that makes the car LOOK dirty, and then once more I wash it with pressure, enough to remove all of the more embedded fine grit, so that when I use the blade, there is absolutely NO grit left on the car. No chance of grit. Of course, I don't dry on a windy day like this, much less wash.
All this said, I think the leaf blower and a quality MF drying towel is the way to go. Maybe some QD as well. While we're at it, a water filter on the hose to remove all the minerals which cause spotting in the first place would be even better. Distillation might be best, but expensive to use.
I would NOT however trust the water blade on a really expensive car that I would be liable for scratching.