Voice over question

As part of my business strategy as a voice over artist, I am always trying to find out more about what my clients needs are. I thought this forum would be good place to fins out some answers.

My main question is:
What are the most important considerations you as a video producer look for when hiring a voice actor for your voice over? Is it based on the voice and voice only? Does having a previous good relationship with the voice over help? Is it price only? Do you actively search for talent or use online casting sites?

I am really looking forward to hearing what you have to say so I can learn more about your side of the industry.

British Voice Over