I've been helping businesses with their PPC ad campaigns for 6+ years now. A lot of clients wonder whether or not I recommend Google Search Ads or Facebook Ads.
I've had several campaigns that I ran on Google Search Ads and Facebook Ads because that's what the client wanted.
In almost every situation, Google Search Ads did a better job bringing in actual customers whereas Facebook Ads lead to mostly vanity metrics like comments and 'likes'.
Even in the situations where the Facebook Ad campaign was generating leads, they always turned out to be poor quality leads.
It makes sense that Google Search Ads would have better results in my opinion. Search Ads allow you to place your ad directly in front of somebody actively searching for a solution to their problem.
It allows you to reach people who have shown intent. You can also target based on demographics, similar to Facebook Ads.
I do believe certain products can be successful on Facebook, but I think it's mostly 'impulse purchase' type of products.
I also believe remarketing campaigns via Facebook Ads make a lot of sense. Although the trend toward script blocking is only gaining momentum, which means remarketing campaigns may no longer be a viable option pretty soon.