If those specs are true, then wow. But, regardless, pitting the S3 against the Nexus is kind of unfair in a way. The S3 wouldn't be available till some time next year (especially in the US). The only real advantage the Nexus would have over the S3 is the fact it will be a pure Google experience and should consequently receive updates faster.
As always, there's always going to be something better around the corner in the tech world.
I'm sick of playing the waiting game so as much as I do want the Galaxy S 3, I'm going to be getting the Nexus whenever it comes out here in Canada. Hopefully it'll release before January when it's time for me to renew my contract, if not then I guess I'll be going with the Galaxy S 2.
I will pull the trigger on the Nexus and feel fully comfortable doing so. Stock > TouchWiz. Who knows when the GSIII will even make it's way to the U.S....the GSII isn't even out yet on the 3 carriers it debuted for. I'm not going to sit around until late 2012.