I do think the NFTD holds more but because the Yeoman is an open compartment, I can fit things in better. I finally accepted that I am, and have always been, a duffel kind of girl.
As I said above, I'm using the REI packing cubes and they fill the space completely. The small length is the same as the medium width, so they total about 17 inches long and fill the bag's length. They are about 3.25" deep but expand an extra 3" if needed. I have them packed full but compressed a bit, so they are roughly 4 inches deep each, leaving enough space for the 3D organizer cube and shoes. The bag is wider than the cubes, so there was just enough room to slide a flip flop on either side.
Nothing moves in there. It is packed tight, tight, tight.
I don't have a Pop Tote (still hear "Tart" every time). I have the Small Zip Shop Bag and I could not get both packing cubes in there.
I didn't think I'd enjoy two-bag travel this much. It really is nice. The mini YD is light enough that it doesn't hurt my shoulder. I use the Simple Strap and it stays on my shoulder on top of the backpack strap of the DLBP. It's also light enough to hand carry without issue.
Just so nice.
Edited to add: By the way, I wear a size 7.5 US, so that helps too. Anything larger than 8 US would probably not fit or something else would need to come out.