GTA IV was expected to be a major system seller but surprised everyone by selling very little hardware (unless we count the Wii which had a unexpected large bump).

MGS 4, on the other hand, seems to have sold hardware in excess of most opinion, Sony included. My question is, why did MGS prove to be a much better hardware seller than GTA?

a. Stronger franchise?

b. Platform exclusive?

c. Bundles?

d. 80GB SKU?

e. PS3 taking off?

f. Snake is a better salesman than Niko and his heavy accent?

Is it some combination or something entirely different?

1. GTA4 did sell a lot more consoles but only for a brief time. Plus it was on the 360 to so you have to count those as well as consoles sold fot GTA.

2. People wanted the bundles before it sold out.

3. MGS is a hardcore game and hardcore gamers want this.

4. Remember MGS has Japan where GTA didnt.

I feel GTA 4 had a huge long term effect since the beginning of this year....and if seen technically the GTA 4 "spike could've been as big as 1 - 2 million extra consoles...

BUT SNAAAAAKKKEEE RULES!

it's also exclusive, paired with the REAL ps3 version (80gig), it's win win.

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.