Also, the 3G runs 3.1.2 slower than it should. The previous major OS 2.2.1 was much more responsive. I don't really mind that I don't have a 3GS because I'm using 2.2.1 and it makes my iPhone fast enough to me until Apple comes out with the next model.
You're like a broken record.
And for the OP, the 3GS is well worth the upgrade, for the speed alone.