Metal Gear Solid games have always been system sellers but back in the PS2/Xbox days Metal Gear Solid was really a system seller. At that point Metal Gear Solid 2: Sons Of Liberty was a PS2 exclusive and that was a big deal. The Xbox's answer was Splinter Cell. An incredible looking game that used shadows as cover.
As an Xbox owner, I loved Splinter Cell. I played it non-stop. At that point MGS2 seemed unweildy and goofy compared to Splinter Cell's accessible, grounded stealth mechanics. It took a while, but eventually I would learn to love Metal Gear Solid 2 and, in hindsight, Splinter Cell seems dull and shallow in comparison.
But let's talk present day. Both of these series have grown and evolved into different things, yet both remain somewhat tied to stealth mechanics. It's hard to argue that both games represent the pillars of the stealth genre: but which do you prefer? Vote and leave your reasoning in the comments below!