How accurate is Glassdoor's estimated salary range in their new job listing?

Anyone had any experience using Glassdoor's estimated salary range on new job listings as part of their negotiation?

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official