As i said before, my S3's spot metering used to work just fine. It worked perfectly for around 2 months and then just stopped dead. I suspect that it was a minor update that broke it. Even the guys in Samsung tech support say that some of their S3's work fine and some dont work at all, so there's definitely a problem.
As for me, I'm using a Galaxy Nexus now. The camera's not as good but I dont have to deal with Samsung's BS anymore and the updates are fantastic!