I think we can't make any comparison between Google and Facebook, both are different, Today Google is everything in the Internet World and Facebook is just for social networking that's it. Yes, we can compare Orkut vs Facebook or Google + vs Facebook.
Google is boss. There two are totally different but I like google for search engine and facebook for social networking.
In terms of traffic, or web businesses, you could compare only generally. But they are totally different. Google is more practical for me for daily use for work and research. Facebook is not a search engine, is more for entertainment and basically it's only value is that people like to feed it their personal data. If it had none of that, it would be useless, but because it has it, it endangers people's privacy. Google is way more valuable in my opinion.
google+ has alot of potential on it but it need to improve alot more to became facebook. so i have to say FACEBOOK !
I stick to those who support both FB and Google. FB Ads and Google Ads are practically the same. Why to choose between the most popular websites?