The collaboration feature in zoho mail is great. However, I wish you address some basic features that were available in other email clients for decades such as able to sort the inbox by clicking on column headers (From , Subject , Date received etc). Also basic things like auto capitalization while drafting the email.

Setting up ZOHO mail as a client for Gmail or others was so painful it took several sessions lasting hours with online support, the same thing took 10 seconds with Outlook. This is one reason I am hesitant to move my email domain hosting to zoho.