I just received my Ergodox (normal case), and can confirm that the TM is truly the most portable option. It is also much more silent that the Dox with browns and O-Rings.
The more you know...
The TypeMatrix is outstanding (typing on one right now), especially with the silicone skin. It was not my primary choice, but I needed something silent, and have not been disappointed.
I'm partial to split ergo keyboards (and have an Ergodox order pending), but the TypeMatrix orthogonal layout, and lightly split layout is quite confortable and also really easy to grasp. It is VASTLY superior to 60% or more IMO, and the orthogonal layout allows for a completely functional numpad as well.
Ergo, silent, compact, not so light but not so heavy, and washable with the silicone cover. Good for me :D
Also, Colemak, Dvorak and all manners of international layout available with the cover system.