Google tracks you 10x more. Do I use GMail. Yes because it is ultra searchable. But I also use track-me-not app for windows.
Yahoo tracks you. They all do. But using Yahoo’s search engine and being tracked by Yahoo is one thing. Using Yahoo’s search engine and Facebook tracking you on Yahoo is another.
I bought the Office365 Business service for email for my family. We do have to pay a little ($4/user/month) but it’s business-tier email that is not scavenged by a Google or Facebook.