I can speak for the advantages of joining PMI..

I joined early this year/late last year and signed up for single interest groups within PMI and there's one for the SF Bay area (and whichever region you live in)...for the SF Sig they have their own website, with job listings and plus I can also upload my resume. I've gotten good calls through them and plus the rates they offer is higher than going through monster or dice...

Also, PMI's great if you're doing research...

--Carrie--