All formula indicate a similar efficiency for both drag and lift (during reel-out phase) power AWES, but without mentioning the swept area.
One can roughly deduce the swept area of Makani M600 from the circling radius (135 m) that is given on some documents like http://www.energykitesystems.net/FAA/FAAfromMakani.pdf.
So the swept area could be something like 13000 m², so far more than 4 times the usual swept area for a 600 kW ground-based wind turbine. Perhaps such a circling radius (leading to the high swept area) is due to flight requirements (?). In these conditions the swept area would be about the same for both drag and lift power systems.
But if several M600 wings are arranged in the same swept area (13000 m²), things can be different as the Betz limit could be more approached, leading to a lesser space/land use.