Users who have preordered the Surface 32GB be warned: it only features about 20GB free once you subtract out the space needed for the operating system, Office, and a few apps. Users who preordered Surface over the iPad because of the double space offered at the same price point will be especially affected by this.
Because of all the space taken up by the default Microsoft installation, the difference in space between the iPad and 32GB Surface really only amounts to a few gigabytes (roughly 5). However, it is true that you can use an SD card with the Surface which will allow increased storage. Apps can not be stored on that external card.
It's pretty incredible that Windows is taking up 12GB of storage when the iPad's iOS only takes up about 1GB. Where does all of this extra bloat come from? Windows RT is a much more capable operating system than iOS, but is it 11GB more capable? It's probably a good idea to take this into account when doing your holiday shopping.