10 points
The “new” version isn’t even a native app… It’s just the web version. It’s missing a whole heap of features from regular Outlook, like support for native add-ins. It doesn’t feel like a native app; the UI doesn’t follow the design standards of any desktop OS.
Also, if you want to use it with an IMAP or POP email server, you have to connect it to Microsoft’s cloud, and they store a copy of your email! https://answers.microsoft.com/en-us/outlook_com/forum/all/imap-without-microsoft-cloud-in-new-outlook/0e17ab6b-48f2-42dc-9e61-f219f7521289
