I have to agree, and I think what makes this possible is if the user is willing to take the time to learn exactly where the tip of their fingers actually are. Apple says it takes a week to get used to the input method on the iPhone, so whatever the case, it's going to take some time irregardless.
I would assume that it takes the average brain at least a week to create new pathways for actions or functions that are new to it, with some people picking it up right away. I have not been so fortunate, however I have learned where my index fingertip is, and I'm faster with one finger than I am with two thumbs on a tactile keypad.
My only gripe however is the suggestion tool. Having to tap the suggested word to cancel using it increases my typing finger's travel time and thusly lowers my WPM.
