I have used New Outlook, and I would sooner abandon MS Office as a whole than give up Old Outlook. Old Outlook is a very decent eMail client, especially in how other programs like QuickBooks and Sage can integrate with it, so I make use of it as a more “corporate” program than others like Thunderbird. Old Outlook feels right. It acts right. It has the right level of utility and responsiveness and age-related maturity.
But I am absolutely unwilling to suffer New Outlook in any capacity. I would sooner give up Office as a whole.