All I know is my personal experience with him. I was PD of a classic rocker in Washington D.C. and we had a midday opening--got the tape of this guy doing oldies in a small New Hampshire market. Sounded great. It was Billy Bush. This would have been about 1995 or so.
Anyhow, met him, hired him. He truly is a great guy on a personal level. You'd never know he comes from money--he drove a beat up Subaru wagon and was seriously "Friday casual" every day! Approachable, friendly, a great sense of humor, and humble. I worked with him for 2 years and was very happy with his work.
I met his dad Jonathon Bush, Pres. George H.W. Bush's brother, and we had lunch at that time. He could not have been more gracious.
I don't listen to the countdown but I catch him every now and then on the Access Hollywood show. He's doing what he's supposed to do in that role--and he's doing a good job there IMO.
Just my 2 cents. For me, Billy's one of the "good guys" in the national entertainment media.