Google Adwords v/s Facebook Ads

[NorMarketer]

Search ads from google are good for meeting consumer intent, but has a limited scale becasue not everyone know they want to buy.

Display ads from google are good for scale, but lot of low quality ad inventory, and mostly useful for remarketing to people who have been to your site.

Facebook ads is also great for scale, and you know that most impressions will be on the facebook page unless you also target instagram and the audience network. Facebook is by far the best way to scale business in my experience.

I would say that you should always use both Google and Facebook at the same time, and understand that they should complement each other.