Oddly enough though, even the enterprise product support can be very bad. I've had dealings with Microsoft over issues related to Azure while under EA, and they

Oddly enough though, even the enterprise product support can be very bad. I've had dealings with Microsoft over issues related to Azure while under EA, and they still took weeks to even look at the issue, which turned out to be a problem on their end. When it comes to big-brand software and services, it can really pay off to buy via a good reseller or consultancy, who often offer much better support than the company that actually makes the product. Of course, that's not actionable advice when we're discussing which mail provider is best for personal use. (Although I suggest the answer is still "not O365".)