What we found at a previous employer through extensive testing: advertising on Facebook works pretty well, but the highest return on ad spend was to not use any of the demographic tools at all. Also, weirdly, having an attractive product and displaying it well in photo and video ads did very well. Almost as if there is no real magic trick of effectiveness at all.
For us google ads was insane. I d encourage Google to keep record on everyone and everything after having seen how incredible their client to business matching is: as a small company, in a niche b2b product (waste management software), we got big name random calls days after starting to pay Google.
In another company we spent millions on Facebook and got relatively little out of it (predatory lending marketing), we had again more success just reducing friction, simplifying the message and putting it on Google with massive keyword spam. The least we protected users, the more they paid us.
