What does the dipping shop use to neutralize the top secret acid once it comes out of that bath? The biggest detractor I have heard on this process is that you never get all the "solution" out from between areas like pinch welds or folded flanges like the door skin. The issue shows up adjacent to these areas as the paint takes on a sheen look just like gasoline on a water puddle. This was caused by the residue mixing with paint & solvents..

The biggest benefit is just as you stated, all the rust is gone...