OK.... I have read all of the posts. Now it is time for my $0.02. The question was "RUST..What are the acceptable permanant ways to get rid of it?"
Now if I take a fender that has a big rust spot on it, and put some of that miricle POR on it, I have not gotten rid of it, permanantly or not. If I cut it out and replace that spot with clean, rust free metal, I have gotten rid of it. Now.... if the rust is just surface and can be ground off to clean metal, it has also been removed.
Placing any product over rust, is not getting rid of it, plain and simple. Although it may slow down the process, it is still there. It is like taking cough medicin for a cold. It hasn't gotten rid of it, just the symptoms.
When I do a car, and it comes time to sell it, I can tell the people that the rust has been removed. If I used POR, and was being honest, I would have to tell them that I painted over the rust. What do you think that would do to the value? Would you buy it? I doubt it!