My biggest issue with the setup was the amount of stuff I was carrying. I've been carrying heavier loads, more than what I used to when purchasing the rack. All that weight hanging of the top of a long seat-post has been concerning for sometime. So I removed the mounting stub from seat-post and sure enough, there were small kinks on seat-post. Nothing severe, but overtime it could weaken the post causing some sort of catastrophic failure. Also, I hate shoulder type bags. Some people like them, I hate them. The rack also sticks out too much and looks ugly when the bag isn't mounted. Lastly, there is a rear rack on my brompton. Why not use a system which lets that rack support all the weight?
For my uses, the cross-rack/crossbar system isn't a good choice if that as the only luggage carrying option. It might work for someone who wants to tour on a brompton and wants an additional rack and bag. But loads in excess of 20 lbs affect the handling ( top heavy......tippy) and jeopardizes the structural integrity of the seat-post. Finally, I've found another system which lets the rear rack support all the weight. I will be posting about that soon.