I have found conflicting reports online whether or not dashes in domain names hurt/help ranking.  Example yourbrandonline.com vs your-brand-online.com?

I found Rand's write up on how to select a domain and he suggests staying away from hyphens but mainly because its hard to remember or people my enter it in wrong.  Here's his comment.

"Reject Hyphens and Numbers
Both hyphens and numbers make it hard to give your domain name verbally and falls down on being easy to remember or type. I'd suggest not using spelled-out or roman numerals in domains, as both can be confusing and mistaken for the other."

Aside from people possibly struggling to get there directly because of the domain name, are they OK to use?  Or, are domains with hyphens considered spammy?

Thanks in advance.