So as said, I decided to do my own comparison. I have 8 just standard steel plates from the hardware store, seven products and one for control. All plates were cut from the same steel bar, sprayed with a degreaser, wiped clean, had their product applied, and then the excess wiped free to leave a thin film. Sprayed two hours ago with a water salt solution.
Breakfree CLP- Looking good. Just to be clear this is the CLP in the aerosol can.
Standard Hoppe's #9 Oil- Defiantly better then the control, but showing some light rust.
Hoppe's #9 with weatherguard- Better then standard Hoppe's, but defiantly not as good as the CLP.
Gunslick Ultra Lube- Looks the best of the gun specific products, very little if any rust.
Mobil 1 Syn ATF (All they had was the multi-vehicle Mercon, says meets Dexron standards)- Defiantly better then the control and slightly better then the strait Hoppe's Oil, but not as good as the CLP or Gunslick.
Marvel Mystery Oil- Looks a bit worse then the ATF.
75% ATF and 25% Mystery Oil- Actually looks considerably better then the strait ATF or MMO, but still not as good as the CLP or Gunslick.
I went with ATF because by all accounts I read, it was better then going with Motor oil. MMO was chosen as I had seen it suggested. And a 25/75 blend of the two just for the hell of it.
Will give another update after they have sat all night, with a picture.
Currently, the gunslick looks the best of them all.