how good are facebook comments links, really?

Let's say my profile is set to public on facebook and I have 250 friends, the average, and I put in a link in a comment on my wall to one of my sites.

How valuable is this?

Compare it to an average blog link on an average blog network site.

Thanks!

interested here as I am really seeing some facebook links ranking really high, especially in medium competition KW's

I'm talking more specifically about how valuable are the links as a method for higher search engine rankings. For larger sites I would want to definitely include them into the link melting pot, but I'm wondering for new sites how well do they work?