Gamerace on 15 June 2008
Various factors:
Exclusive
More core than GTAIV (which had a large casual following too)
Limited bundled version
Japan
However, just because it caused a more notable spike in sales does not mean it pushed more consoles. Far from it. GTAIV will sell or help sell more consoles in the long run (split between 360/PS3) but MGS4 will be a more pronounced short term boost.
