I tried "1 Step Rust Killer" from IPI. I did a lot of research and it seemed like it was a good product.
I wasn't satisfied. I had done what I thought was more than average preparation, and applied per instructions, but in the end, I had to really get aggressive with the deteriorating metal. Then, instead of using more of the rust converter, I rolled on good ol' rustoleum metal primer with "rustoleum stop rust". I then painted over that with rustoleum white oil based.
While most of the painted areas are covered, there's still some exposed, namely my entry steps and the back two seat areas. I'm walking on and putting tools down on these areas all the time. Tough as nails.
Bottom line, I'm not too sold on the rust converter and heavier areas of rust. I think if you are going to use the rust converter, you need to get pretty aggressive with the rust removal.
Hope that helps.