OK my two cents is that I have always used ARO and I have never had rust in an engine, people can debate all they want but the results are negligable.

The condensation your talking about has a lot to do with relative humidity and temperature differences. If somthing is hot in a cold environment it will repell water because the air around it will be thinnner due to the heat and vise-versa for somthing that is cold in a hot environment, give there is enough humidity in the air, thats it.
Hot=expands Cold=contracts