I am an aviation nutcase...from what I have read regarding the A380;
Cleon is correct: The benefits of the A380 is lower fuel burn per seat and lower operating costs per seat.
The customers who have placed orders for the A380 are: Singapore Airlines, Lufthansa, Emirates, Air France, Qantas, Malaysia Airlines, Virgin Atlantic, International Lease Finance, Qatar Airways, Federal Express, Korean Air, Thai Airways, Etihad Airways and China Southern Airlines. It costs between U.S. $263 and $286 million.
The great thing about the A380 is it was designed to meet the Airbus Flight Operational Commonality...that is, it has a similar flight deck to the A320, A330 and A340 which makes for easy crew transition training, cross crew qualification and mixed fleet flying.
Maximum operating speed is Mach 0.89, (most passenger aircraft are .85 or less), and the range is 8000 nautical miles with maximum load. Also, turnaround time at the airport is minimum 90 mins and it has ten fuel tanks carrying 131,000 L of fuel - refuelling in about 40mins.
There are roughly about 20-25 airports worldwide who can handle the A380 currently. The biggest hurdle is the weight and width of the A380...most airports are concerned that they will have to rebuild or widen taxiways and runway bridges to accommodate the 540 tonne weight and 78 metre wingspan.
All in all it is an amazing aircraft, Boeings' answer to it is the 787 "Dreamliner".