I've been using Krown since '98 when I first bought my '92 Cressida. I finally put the car to rest in 2012 after 500K km. I bought my '98 GS400 in 2007 and have been using Krown on it ever since. There is virtually no rust on the car except for two or three tiny little spots up by the top of the windshield and at the edge of the trunk bar. All of the body panels are still totally rust free. I live in Ottawa and drive year round, winter and summer averaging over 25K per year.
I have also used Metropolitan rustproofing on my Cressida a few times and also my 97 Camry (also practically rust free). Seems to de basically the same thing as Krown. My Daughter just krowned her 2009 Is250