VGChartz's William D' Angelo:
"Wii U Vs. PlayStation Vita Global:
Gap change in latest month: 511,711 – Wii U
Gap change over last 12 months: 873,463 – Wii U
Total Lead: 631,401 – PSV
Wii U Total Sales: 12,466,964
PSV Total Sales: 13,098,365
In the latest month the Wii U closed the gap when compared to the PlayStation Vita by 511,711 units. In the last 12 months the Wii U has closed the gap by 873,463 units. The PlayStation Vita currently leads by 631,401 units.
The PlayStation Vita first launched in December 2011, while the Wii U launched in November 2012. The PlayStation Vita has sold 13.10 million units, while the Wii U has sold 12.47 million units."