The ultimate laptop bag (for my particular life style) is a waterproof backpack. I have a backpack that is a drybag-rollup style. And I've had my laptop in it and had it go underwater (paddleboard flipped while going down a river), and in a rain storm that came out of nowhere. No problems. Also, it's nice to have the peace of mind that if I was out somewhere with my laptop, I wouldn't have to worry about it raining. For me, the primary factor of consideration for a laptop bag is a bag that will protect my laptop.