So, to mix it up a bit and also to assess if I will forego any of my 'regular items', I have been taking the Carradice Nelson Long Flap Camper (NLFC) on a few days. The Carradice NLFC is a great bag, but I sure wish it had a should strap, as my commute is multi-modal and I do take my bag off the Brompton, while I am on the train and the bus. During these times, I have to carry the bag by its strap, which you can see sticking above the saddle, in the picture below. It is okay to do this and that is the very purpose of the handle, but I lose one degree of freedom, so to speak. I don't have both my hands to hold on to poles or straps, to steady myself, on the train and the bus. The T-Bag has a very nice shoulder strap, which is very useful, while on the bus or the train. One more good thing about the T-Bag is that it has a strap in the front which can hold my helmet/hat - see this link for more details.
One other nice feature in the T-Bag is the water bottle sleeve. The NLFC has a pocket for holding my water bottle, but having the bag behind the saddle makes it difficult to reach for the water bottle, while riding. No biggie, in the grand scheme of things, but I am working on finding a solution for this. I might even consider adding a water bottle cage to the Brompton. The evil twin wants to get a Brompton City Folder bag for the front, which is a bit smaller than the T-Bag and quite stylish, but I do believe it weighs a bit more than the T-Bag. Evil twin's argument - You don't have to carry all your junk in the new bag you know.
So, while I am not dealing with a real/life issue or something, I am dealing with a quandary. One that is created by me and quite possibly is one that will be 'solved' by me.