When selecting a bag for commuting with a laptop, take note of where the laptop lives in the bag. Messenger bags work way better if the laptop storage "floats" toward the front of the bag away from your back. This allows you to put soft things close you your back. Your torso is round and putting something hard and flat against your back focuses the weight of the whole bag on a small patch and turns the bag into a teeter-totter on your back. With soft stuff near your back, the bag can hug you and will be much less likely to slide around the side as you ride. This is less of an issue with bicycle backpacks, but I still think away from your back is better. When the bag is on the ground or leaning, the laptop is resting on the cushion of the rest of your bag, instead of the bag resting on the cushion of your laptop!Among others, Mission Workshop messenger bags and their larger backpacks get this right.