Try the G version of the 50mm1.4. I got it and its silent and cheap ($500)
As for the 24-70, I received it last week and barely touched it yet. I am between jobs and got very little time to do so. And the time I had was while watching the hockey game and messing around with it.
I got mine for 1341 usd shipped and its really brand new. But I consider myself lucky since I couldnt find any under $1500 when I was looking for one. The guy could have sold it as new and I would have been forced to believe him.