As Sparky said both are good it depends on what you like in looks and that may change after you take the class. I am building with Ponderosa and the thick bark seems to come off easier then the thin stuff but thats all on Ponderosa I have never peeled any Lodgepole. The Lodgepole might be a little easier to work with being more uniform and not having as many knots. However I prefer the knotty gnarled rustic look myself rather then the more perfect look. Different species have more or less resistance to rot however the real key is keeping the logs dry with proper overhangs which you'll learn about in class. Keeping the logs dry can really make any difference in rot resistance negligible.

Blayne