Well, our work just moved over to Microsoft 365 for email and I’ve been using web access. There are a lot of things wrong with. Now it may be Microsoft’s implementation and the way it works and plays with Firefox, but:
a. It’s slow. Lots of spinning arrow thingies while it mysteriously decides to pop up new windows.
b. When you click the “Keep me signed in” checkbox, it doesn’t. When you try to log back in, it often doesn’t recognize the password (no, I’m not typing it wrong – the system is buggered – if I bring up a new 365 login, it works).
c. The interface is different than the one I’ve gotten used to and I don’t like it very much.
d. Did I mention that it’s slow?
It’s not terrible, but I prefer a dedicated application.