I had my car dipped. I have mixed feelings about it. The car itself was very rusty. I had replaced as much sheet metal with better parts as possible, and the replaced metal was in good usable shape. Those parts after dipping came back looking like brand new parts. They were beautiful. Clean, no surface warping or texture from media. Of course the edges were sharp and I had to be careful of slicing my hands open.
The body was another story. The body was really rusty. Dipping didn't get all the rust off like I had hoped it would. I even took it back and had it dipped a second time. Still didn't remove all the rust in the recessed areas, crevices, etc. Don't expect it to get the rust in the pinched weld seams. Then again, media blasting won't get in the seams, either.
Now, my car is still apart. I'm doing it myself and I can only work on it so often. I didn't primer it right away, as I'm taking it apart and replacing panels, etc. It didn't rust over on me unless I got it wet. That seemed to reactivate the acid trapped in the seams.
From what I've read it can do this for up to a year afterwards. I'm only 6 months through. I've been spraying areas I've fixed up with rust encapsulator and it's working well.
I have pics on my build thread. I hope this helps.
https://lateral-g.net/forums/showthread.php4?t=26338
-Brendon