My understanding is the newer Android/iOS apps (and maybe Windows/Mac, who knows) filter everything through Office 365 in some way, even if you're using Exchange or your own server. Is this following the same model?
Very clunky feeling. I like the looks (although takes time to get used to), but even animations such as window resize stuter.
I used it all last week, and if I had the Outlook window minimized, new emails and calendar alerts wouldn't show up. Finally switched back to old Outlook during a meeting I joined halfway through (due to the missing alert).