I didn't get to see hi in action at all while in Oakland, but I remember him showing some ability while in Arizona. I don't remember being wowed, but I remember thinking he could develop into a nice QB. He serves as half decent insurance against Beck craping out I guess...not much more at this point.
On the other hand, I felt the same way (as I'm sure many did) about D, Anderson in Cleveland, and he did pretty well for himself last season. We will see!