My 2 cents
As someone who hates ms but needed to use a mobile email application from them, prior to this clusterfuckery their outlook app from the play store was outstanding. I use my ms account for uni and we frequently get last minute changes emailed to us so keeping something on my phone made sense.
The main issue I have with the new outlook is that it doesn't alert you efficiently when a new email comes in. It might on some days and not on others and it might just be me but their spam filter seems to be taking garden leave.
Ironically, the only truly excellent software they (ms) ever provided imo was that app prior to changing it. Shame really, because it was flawless.