Well, according to the Wikipedia page, and I don't know how accurate this is, but they say that it has 3.3 million square feet of floor space. The tower is extremely slender. The WTC towers were 4 million square feet each, as is the Willis Tower. The problem is Dubai has 20+ other 1,000+ foot tall towers under development, too. So the market is over supplied.
Here's an article that says there's 30 million square feet of office space coming online in Dubai. And that's just office space. It doesn't even include residential, hotel or anything else. It says the total square feet on the market for office space is 48 million. That's not all that high actually.
http://www.nuwireinvestor.com/articl...ncy-55565.aspx
3.3 million square feet in Dubai is a drop in the bucket to their market.