Exactly what Eva has said for all the reasons she has outlined. My carryon is a different brand, but looks and sounds like an identical twin. I chose black because it is practical and looks like luggage, not gear. I also upgraded the shoulder strap to a more comfortable, padded one. I use packing cubes to keep everything neat and accessible, as well as to serve an an internal compression system.
I am also a huge fan of plastic Ziplock bags for compressing and packing items. I can fold my full-length raincoat into the large size, expel the air, zip up the bag, and slide it easily into a pocket.
Having a bag that is more or less the same size and weight of some of the tote bags I see women carrying on a regular basis means that no one gives me a second glance in a major metropolitan area. I like that.
ETA: I also refuse to carry a pack that weighs more than 12-14 pounds; with a bit of planning, and some judicious elimination, I have no problems traveling for a month or more with just a carryon--and looking good enough to stay in five-star establishments. Actually, if you have enough for a week, you have enough for any number of consecutive weeks. To my mind, it has always made more sense to do a spot of laundry rather than to haul around pounds of dirty clothes. I like to be the boss of my suitcase, not vice versa.