They tend to all agree that having a BBB accreditation is a no brainer for local SEO purposes. It is a good link in general to have, plus it is a solid citation for Google Local's algorithm. Of course, it is hard to prove but BBB, even though you need to pay for it, it is a solid organization that people go to when they have problems with local businesses.
I have paid for it for years for my company and I place it on my side bar on the inner pages because it is a trust building logo that people in the US recognize and mostly respect.
Honestly, I never thought if it has any ranking factor - I just did it because of the trust.
Do you think it helps with local SEO ranking?
Forum discussion at Local Search Forums.