Scotty,
I used the TwoBobs AMRAAM set and they went down like a dream. After applying per the directions I couldn't even see the edge of the film. My only complaint was that all of the decals for one missile were one decal. While this really helps with placement, I had one fold over and getting it unstuck was a pain.
If you want to try, you can use some of the liquid decal film and put it thinly over the old decals and let it dry before trying them. It should help keep them from falling apart.
Groot