I used Nine for work email for years; it has the fewest “deal-breakers” in an email app that I’ve ever tried. Unfortunately, my company changed to Exchange Online and now only allows the official Outlook app.

As someone else mentioned, it’s UI is maybe a little cluttered. However, it’s also got the all the features I wanted. If you favor clean UI over features, look elsewhere. Otherwise, it’s worth the price of admission.

They replace AP with something else internally and abandon AP. If anyone wants to keep talking to them, they’ve got to hop onboard whatever they’ve replaced AP with. This effectively kills AP (theoretically).