The comments here are ridiculous. 2FA works fine if configured right, ours only checks in if outside network and only once per new device every 14 days. 365 works fine as well. I have had some issues using Web Excel, but all desktop apps work pretty much the same as the others. Outlook with the try new version is the only pile of trash I've seen. Other than that, the one thing that does suck more than any of this is its ridiculously expensive and subscription based. The fortune we spend now and monitoring needed to be done on licenses and space used is also frustrating. Mail only offering 2gb unless higher license level is crazy especially for how much you're paying them.