I've seen about ten major Office 365 outages since my last major Exchange upgrade? I don't know how beliefs about cloud service uptime being good persist unless your IT staff were really, really bad at their jobs. My house is more stable than a MS datacenter. And by and large, I actually like Microsoft.
I would not call this a major outage. The service still worked, just not from a single client app, many apps still worked as did the web interface. My house is more stable too but my office is not. I've had UPS systems fail. I've had ISP outages. The overall up time is better, in the case of Exchange, than I could make it at the office - especially considering the 24/7 nature of email today. We need fewer IT people because we offload some of the work. I don't want to be Rambo.
I would say I've found "cloud engineer misconfigures something that knocks the whole service offline" happens more frequently than "my building has a hardware, power, or ISP failure". To some degree, I feel like cloud services have, after overengineering their redundancies for such common failures... introduced a far worse failure via their extremely sophisticated update cadence and orchestration systems.
I'm not a huge fan of cloud in general. Office 365 provides a lot of value for our organization. In addition to Office and Exchange we get a bunch of other things like Sharepoint, Forms, Flow, etc.
I had terrible problems with hosted Exchange from Intermedia. I've had pretty good luck with Exchange on Office 365.
Office 365 support is absolute garbage, they really want to punish you for contacting them, especially so if you've found a bug.
I've seen about ten major Office 365 outages since my last major Exchange upgrade? I don't know how beliefs about cloud service uptime being good persist unless your IT staff were really, really bad at their jobs. My house is more stable than a MS datacenter. And by and large, I actually like Microsoft.