Yahoo is older than Google, but Gmail getting popularity and users. Easy always very fast spreading, Gmail is a user friendly. Gmail is a Google product, I have Gmail for my Android phone and getting more apps from Google play store.
Gmail compulsory for using Android phones, getting Android updates regularly from play store. And. Google products are registering with Gmail. Mainly play store not working with out Gmail, without Gmail you can’t install any application from play store.
You are eligible for 15 GB cloud storage free, when you’re created account. And you can create a free blog also with your Gmail.