There is many ways to use the Structure Sensor, Occipital did a great job!
You can use the sensor with the Ipad via their free applications 'Scanner' and 'Room Capture'. The scan (.obj) will be turned into a zip and you can export it by email.
You can use the sensor with the Ipad & a laptop (recommended) via the application 'Skanect' running on the laptop and the free application 'Structure' running on the Ipad (mode Uplink: the laptop and the Ipad are connected via an ad-hoc wireless connection). From 'Skanect' you can export your 3d scan in .ply, .obj, etc, but not .fbx straight. Skanect is awesome and the result seems better than by using the apps 'Scanner' and 'Room Capture'.
You can use the sensor without an Ipad, via usb connection to a laptop/desk computer running 'Skanect'. But then you don't get the color information (the sensor uses the camera on the Ipad for that) unless you hack the system.
You can also hack the sensor the way you want to, I don't have time for that yet but some do and I can't wait to see coming applications dedicated to this awesome device!
If you plan to import your 3d scans in Unity, I definitely suggest to learn a bit about how to clean/simplified a mesh (Meshlab seems good enough and free). If you import it straight in Unity, it creates lag (the .obj is too big) and you don't want that.
So far the structure sensor seems to work greatly!