Great points: I think that, however, (1) would certainly change if the U.S. changes its online gambling laws, and (2) this is still in development. Facebook certainly can’t touch Google in paid advertising at the moment, but look for that to change as they get a handle on just how to do it. (They’re working on it, trust me.)
At the moment, Facebook’s big advantage comes in networking and getting word out on your branding to the community — that has SEO impact, and as Facebook monetizes its traffic, and evolves its online gambling laws along with the rest of the world, Facebook has a real shot to overtake Google.
Doesn’t necessarily mean it will happen, however; Facebook could be just as irrelevant in five years as MySpace is today. It’s worth considering, though; particularly if you’re planning to grow your business in the next five years, as we all are.