The two main A99 competitor are now shipping worldwide and at first glance it appears that the Nikon D800 sells more than the Canon 5DmarkIII. See the Amazon US rankings (Click here). According to my trusted sources Sony has two new FF sensors, one with 24 megapixels and the other one has 36 megapixel sensor (used for the Nikon D800). I am pretty sure the A99 uses the 24 megapixel sensor. But we are just a rumors site so everything is possible
The main and very basic question you should answer is:
Now I am curious to learn what you need!