I've only started a Facebook page to correlate with my redwood pages, as a way to trigger a boost in Google Adsense income.
For business though, I'd hate to let a Facebook page pull away from my investment of time in my main website page since that's the Granddaddy for leads and income presently.
Its still pretty much that good websites rule and Facebook still drools to some degree. Still worth toying with. FB should pan out for Rank and File stuff like lawn mowing, toothpaste, coupons, etc.. The kind of stuff where bargain hunting is high on the totem pole.