To settle all the confusion about the TouchWiz interface and whether or not it will be included on the Samsung Galaxy Tab 10.1, we reached out to Samsung. They let us know that the TouchWiz UI will not be available at launch, but will come via a separate OTA download for all Wifi Tab 10.1 users. We'll certainly let you know when this happens.
This begs the question -- if you buy a Galaxy Tab 10.1, will you update to the new TouchWiz UI? From everything we've seen and used, it's a beautiful interface that takes full advantage of the real estate of a tablet's screen. Personally, I'll be sure to check it out, then make my final decision. What say you? Sound off in the comments and discuss further in the forums!