I haven't jumped on the waterless wash method yet. I have tried it, I just don't think its the same. I had to wash a Ford F150 today. Nothing beats pressure washing out the wheel wells and undercarriage. Maybe on a really really clean car I can see waterless working for just for a quick upkeep but I'll stick to my PW and foam cannon.
When it's 12 degrees outside and/or you don't have access to an outside hose (such as an apartment, like me; or a lot of folks shut their water supply to their exterior spigots off in the winter to prevent freezing as they are sometimes not well insulated), then waterless washing is a godsend!
That's my case. In the winter, it's how I was. I will run to the coin up and knock the brunt of the dirt off, and power wash the wheel wells and that sort of thing. Then I come home and do a waterless wash (As a power washer only goes so far unless you do a 2 bucket wash!).
I don't do the garry dean method though. I do the good old spray-on wipe-then-buff off method. I use two-sided towels (several of them). Spray a panel, gently wipe it down, top to bottom, with the fluffy side. Then flip it to the thin 'buffing' side and buff the panel to a dry shine. Takes 10 minutes (or less) to get the whole car clean (minus the time at the coin-op if necessary) and gets the car very clean! EXCEPT of course, for wheel wells and such. But it gets the majority of the car clean without a hose, a lot of effort, or spending a ton of time outside freezing to death. To me, that's where it is so useful! 6 towels does the paint, another 2 towels does the glass and another towel does the wheels. That's, consequently, just enough towels to throw into the washing machine on a 'small load'. And I find when they get tossed into the washing machine still wet with the waterless wash solution, (not allowed to dry and stain), they come out looking brand new. Even my wheel and glass towels! (I do use a MicroFiber detergent)
The waterless wash works well on waxed wheels too. Maybe not a german sports car, but a domestic plain jane sedan like my car, which has very little brake dust, it's no problem. I take a wheel/engine/door jamb only microfiber towel, and clean all of the wheels using the same spray down / wipe off method. I use the waterless wash solution instead of a wheel cleaner as it leaves no streaks behind!
All in all, I get a pretty darn clean car. Not as good as a two bucket wash, but it takes a whole lot less time (which is nice when it's below freezing!) and doesn't require a hose.