According to internal VGChartz estimates, sales of Microsoft's Kinect sensor passed the 4 million unit mark as of last week (week ending December 11th). This puts Kinect on pace to sell over 6 million units by the end of the year. Xbox360 hardware sales have seen a significant lift since the launch of Kinect with around 40% of all Kinect sensor sales worldwide coming via units bundled with Xbox360 hardware - clearly showing that Kinect has been selling outside of the existing Xbox360 userbase.
In the same timeframe from launch, Nintendo's Wii managed to sell 2.9 million units and Sony's PlayStation Move sold just over 900,000 units (camera + at least one Move controller) - less than 1/4 of the sales of Kinect. Despite the shortages experienced by Nintendo in 2006 and despite a far more aggressive marketing push than Sony had with Move and the effect of holiday boosts (which Move did not have in the initial 6 weeks), Kinect still looks to be the clear winner of the "motion wars" at this early stage. A fairer analysis will be available after 3-4 months from launch (when the effect of seasonality and shortages will even out) and we will revisit these comparisons at that point.
Stay tuned to VGChartz for the latest Kinect and Move sell-through updates.