I don't like Outlook but compared with new Outlook its amazing
I've been forced to use Outlook for decades and I have a hate-hate relationship with it. However I have tried new Outlook a couple of times at work but I couldn't get on with it at all, and went back to classic Outlook.
For me the biggest problems were the very-very poor performance, I've got mailboxes with lots of emails in them, and it was utterly terrible when switching from folder to folder.
The second issue was that the GUI change to web behaviour so the click behaviour is wrong. and you need to relearn what left and right click do, which was just painful - after too many times of hitting the wrong button I gave up and switched back.
Outlook isn't great, and has been my least favourite email client for years, but now it has been supplanted by new Outlook which is actually far worse - something I didn't think was possible.
I also have to use corporate Gmail, which isn't exactly that good either, but it's still a lot better than new Outlook.
I will actually miss Outlook, which surprises me...!