I'm also finding the touch sensitivity on the S3 a bit variable. Its super sensitive, almost overly so, over the back button area, so when I lean my thumb across the screen I frequently end up going back by accident. But sometimes when I touch other parts of the screen it just doesn't respond. At all. I have to try several times before it does anything.
It's worse in the browsers. I was using the stock browser but then added Dolphin to see if would help and its possibly not as bad, but is still a problem at times. It also happened yesterday when I was just killing time playing a game, which when you're in the middle of a game of jewels is just a tad irritating ;).
I'm not new to the Galaxy S range. I had the first Galaxy s since July 2010 and my husband has the S2. So I know I'm not handling it wrong or anything.
Does anyone else have this problem? And is there not a way to adjust it? Or have I possibly got a faulty screen?