>>I can open several emails at once and compose several at a time. Can't do that with Gmail.
With the new Gmail compose, you can... sort of. It will stack them at the bottom, but only show two "open" at a time (at least on my comp, with a fullscreen chrome window on 1900x1200, maybe you can have more open with a wider screen).
Not ideal, but better than it was at least.
I've been using my Yahoo account for over a decade. Why should I switch? I would have to change all the services that use the email. I never get spammed on Yahoo, despite it being a very old account.
I actually prefer Yahoo over Gmail since it has tabbed emails. I can open several emails at once and compose several at a time. Can't do that with Gmail.