one improvement to Q-A strap
I love the Quick-Adjust strap I got with my ID. I used an Absolute with my Empire Builder and ordered another one with my Aeronaut. But I agree - for daily use, the Q-A strap is excellent. I love being able to change the bag's position so easily.
The one thing that I don't like about the Q-A strap is that it's too slick to reliably use hanging off one shoulder (bag on right side of body, strap over right shoulder). This same slickness does make the bag great when used across the body (bag on right side of body, strap over left shoulder) because it means you can maneuver the ID from behind you, to the side, to in front of you to get inside the pockets - all with ease.
Still, it's scary when on really short trips - like from the car to the front door - and you need both hands free, and you want to just sling the bag from one shoulder. I've had the ID drop on me once.
I think a perfect upgrade for the Quick-Adjust strap would be a small strip of rubber (similar to Absolute grippy material?) on the *top* of the strap. This way, normal use would be as before, taking advantage of the slickness for maneuverability. But for those times when you want to walk a short distance with the bag off one shoulder, and need a little more grip, you could flip the strap around and put the rubber stripe down. This would twist the straps - but again, it would only be for occasional use - and would be a much more reliable method of one-shoulder carrying.