I knew this would come up...
I actually expected the apps argument to be presented in the comparison and was surprised when it didn't. You're right that iOS has far more apps available that Win RT, and even though MS promised over 100,000 new apps in the store by end of January iOS will still trounce it.
That said, there is no Office for iOS. That's huge. It will take time for Win RT to catch up, but with developers being able to easily port their app from Windows Phone to Win RT tablets to Win 8 desktops I think the ground will be made up quickly.
And while the Surface Pro is not really comparable to the iPad since its hardware is so superior, being able to run compatible Windows applications opens up a market far larger than iOS.
