How do you backup your email to your home server? Is it just an mbox dump via takeout on a cron schedule? How would you restore it in the case of leaving Google?
Just used this to backup my inbox the other day. Compresses emails into .eml.gz files. Also has an export option for other mail clients. Love that its a Python package, Installable through pip.
Set up a cron job for that (after a full initial sync), and should be good to go.
Gmvault gets chats as well (I'm assuming hangout chats also). A pro I see, is with gmvault you can restore the backup to another Gmail account, right from the terminal.
Takeout stores chats separately, not in the mbox file. To restore from Takeout, you need to add the mailbox to Thunderbird (or some 3rd party email client), add the account you want to restore to, and then drag and drop emails between them. Not ideal.