mbox format is horrible, because if the irreversible "From" quoting it requires. And as an "editable" format (e.g. If you want to delete an email in the middle

mbox format is horrible, because if the irreversible "From" quoting it requires. And as an "editable" format (e.g. If you want to delete an email in the middle of it), it is perhaps the least robust possible. Maildir is ok. Mbox couldn't be retired early enough.