I have the bag in Cammeo and had the same concerns you have about colour transfer and whether it was high maintenance before I got the bag. I don't believe in "baby-ing" my bags, but I do make a conscious effort to watch where I place the bag, and ensure that I'm not wearing dark denim when I am carrying the bag, which is easy cos I work in a no-denim work environment. Heh.
My BN2274 comes with a shoulder strap, and I was told only BN2274 and BN1801 comes with the detachable shoulder strap. You might want to verify and confirm that with some of the other members here. BN1801 is the smaller version, with magnetic closure and single zipper, whereas BN2274 is the one with double zippers.
Hope that helps, and you get the bag soon!