Join a writers union?

I've been fighting with myself over this decision, literally, since 1999. I've thought long and hard about joining the National Writer's Union and the Maine Writers and Pubishing Alliance in hopes it would somehow benefit my career. I've heard both good and bad stories/opinions about unions and alliances, which is why I'm so torn. I have a very good friend in the industry who swears by the National Writer's Union and she's very successful . . . however, she attributes very little of her success and insurance benefits to this membership (she's insured through her husband). There's a site, http://www.selfemployed.com, that used to supply insurance information to people like us who are working for ourselves in the writing and pubishing industry. I stopped investigating this issue when I learned of a health program offered to residents of my state. There's also a thread in the forums at http://www.absolutewrite.com and, I believe http://www.writersweekly.com in the forums covering this topic. A search will produce the results, if I remember correctly.