PlayStation Vita / PSP
Three out of 2012's four highest-scoring handheld games (not including iOS) were found on the PlayStation Vita, and the first-year platform also edged out both Nintendo handhelds in average Metascore for 2012 releases. The Vita also managed one 90+ release: Persona 4 Golden, a port of the PS2 game Shin Megami Tensei: Persona 4.
The number of scored 2012 releases for Nintendo's 3DS and Sony's Vita were virtually identical (77 vs. 76), but nearly 45% of the Vita's games received positive reviews compared to just 31% of the 3DS titles. Nintendo, of course, still has the edge where it counts: in hardware and software sales.
3DS 2012 Avg. Metascore 66.2
DS 2012 Avg. Metascore 67.6
Wii 2012 Avg. Metascore 67.9
Wii U 2012 Avg. Metascore 68.6
360 2012 Avg. Metascore 69.5
Vita 2012 Avg. Metascore 69.7
PS3 2012 Avg. Metascore 70.3
PC 2012 Avg. Metascore 70.3
PSP 2012 Avg. Metascore 71.2 *
* = Includes Minis, also compatible with PS3 and Vita
http://www.metacritic.com/feature/best-video-games-of-2012?page=1
http://www.metacritic.com/feature/best-video-games-of-2012?page=2