I disagree with your knowledgeable friend on the Giant Brand. Giant has been making bikes longer than most manufactures and has built many of their bikes as a contractor. Giant makes great value bikes. Don't rule them out.
This has already been mentioned but having disk brakes allows you to run larger tires which can make a world of difference. For some this is not something they value. People having been riding 28 mm tires for years with ill effect and you may be one of those people. One of the other reasons I like disk brakes is how effortlessly it takes to squeeze the brakes. When it is cold and you are wet, the pull on the hydraulic lever is something a caliper brake and cable will never equal. The modulation is also an advantage.
Every bike you listed is a great bike but some are very different from each other. Most of them are endurance fits which means a more upright riding position. Typically longer head tubes among other things. The climbing bikes will be more aggressive, with more saddle to bar drop and quicker handling. Which ever you choose, good luck.