Zoho is pretty good and a serious company, but I've had some trouble with them a few months ago (they were dealing with severe flooding) and it was on a really bad timing for me (I was expecting several critical emails).
After evaluating the alternatives, I'm still with them (both Google and Microsoft were too expensive or didn't support what I expected), I only wish they'd been more upfront with their issues. They did write a blog post later, and I think they've learned:
[1] https://www.zoho.com/mail/zohomail-pricing.html