Well, I'm considering a new laptop this holiday season, and at the MBA's price point, I'm choosing between
-Asus Zenbook Infinity
-Sony Vaio Pro13
-Apple MBA 13
-Lenovo Thinkpad X3 (if it gets released in time, looking doubtful. Will probably consider T440 though its a bit bigger)
The biggest advantage the MBA has over any of those is battery life; and if the vaio is any indication of haswell ultrabook battery life, the MBA's advantage in this area is
slim to none.
Based on what I've seen of the Zenbook Infinity, if it gets comparable battery performance to the Sony, I can not think of a single reason I would choose the MBA over it.