As a MENTOR, Diamond was above average without being great. He didn't say anything stupid, ignorant, or condescending, which already puts him ahead of the majority of them. And he didn't overly praise any contestants, sucky or otherwise. On the other hand, he didn't give any noteworthy advice, either. As a SINGER, however, I was very impressed. He's still got most of his range and it was a very good song. I'm also mighty impressed with any 67 year old whose mother is still alive (mine died last year).