> One question I have to more experienced Emacs users: Can you recommend an email client?

Contrary opinion from an experienced Emacs user (parts of my init.el are older than many users in this forum): I used to be a fan of Gnus, but then noticed that dragging attachments into E-mails is such a productivity booster than I switched to Mail and haven't looked back. If you are on a Mac, the combination of seamless drag&drop everywhere, Mail.app and LaunchBar simply does not compare to what you get inside of Emacs.

I do feel some regret, because I liked the customizability, but facts speak for themselves: I do things much faster with Mail.app.