Ask HN: How do you evaluate a recruiter?

When you are contacted by a recruiter on linkedin or elsewhere, what are the things that are positives or negatives for you? Personally, it drives me nuts when I have to have a back-and-forth to get them to send me the job description first rather than a phone call. Conversely I am so happy when someone just provides the information up front; even if it is not a good fit, I am happy to work with them.

What are your positives/negatives?