Used call screening for the first time yesterday, it worked really well. It was a call I wanted to take, but from an unknown number which was actually a call centre, but when I saw their response, I knew what it would be about, so took the call.
I've been using call screening for a while. It's a shame that it's not an app that I can download to my other phones as it's very handy for cold callers - you can see they hang up pretty quick.