I find the extra space useful over just a laptop screen for coding - I can have a simulator to one side, and a coding window open with a good amount of space for metadata sidebars, along with a window or two for code documentation.
Where it really shines though is for photo review and editing. There it is spectacular to have so much space for image review even with a good number of adjustment controls up.
The other thing the screen is great is for use on a plane. No-one can see what you are working on, but it's also a kindness to others since your laptop screen is totally dark. It was really nice working on an international flight with the AVP and a laptop.