I get a moderate amount (50-100) emails a day at work. I deal with them mostly on my iPhone and Mac although I do not always have access to my Mac for long portions of the day. I am looking for certain email functionality which I do not seem to be able to find in one email client that I can use on both iOS and Mac. Primarily I move most of my emails to folders. This is time consuming on the apple mail app. Some of the others (Spark, etc) seem to be quicker and more efficient. I have found though that with other email clients, especially on iOS , the search only seems to be able to look in the inbox, sent, archive, etc but not into subfolders, especially if they are on the server. The native Apple mail app seems to be able to find most of the emails I need but not other clients.
The other need I have is to be able to snooze email for a period of time. This is not something the Apple mail app can do but third party apps can. I know I could use a server side solution such as SaneBox but this does not solve the moving of emails to subfolders and finding them later.