I manage over $100k/month in adwords advertising spend for clients who demand results. I've also spent a few thousand dollars on Facebook ads for those same clients. Facebook ads do not work as a direct response type of advertising.

However they work fabulously well for sending traffic to your company Facebook fan page and building your fan base. You can typically get new fans for about 40 cents to a dollar a fan. These are people who you will be able to influence on a daily basis for years to come, and although you won't be able to directly track sales/leads/whatever to your Facebook advertising, I also believe there is tremendous value in interacting with your fans in this more personal way. It's a lot harder to convince clients of this value, but it's real.