I wouldn’t know. The only emailing I do is on the stock app on my iPhone or with the web interface of either Hotmail or Google, as I have both services.
And since I somehow trust Hotmail more than Google, I do semi-serious stuff on Hotmail. Signing up for apps and web services with Gmail.
The reason that I use Gmail for non-serious stuff is because of the interface. It’s too ‘sans comic’ for me. I can’t take any service with that kind of UI and font serious. And since they don’t support push notifications for the stock email app on iOS I don’t feel any bad about not using Gmail, at all.
When I switched to iOS a few years ago, I forwarded my Gmail address to my iCloud address and no longer use the Gmail app, but the mail app on iOS. I also use Outlook but for work email, that way I'm keeping work and personal separated from each other. I do like how I can see shared calendars in the Outlook app that you can't do on iOS app.
I hate outlook/Hotmail but stil use it. I also use Gmail and Yahoo. As far as the others on the list and I realize Yahoo Was not on the list, I don’t use any of them. I access through the stock app on both my iPhone and my iPad.
If Apple combines the calendar, email and reminders into one app, it would be a dream for me. I've tried them all except for Timyo. I still use the native Mail app for my personal email accounts and Outlook for my work email. Edison, although it was called Easily.Do when I last used it, was very nice. I haven't used Spark in quite some time and It's been eons since I last used the official Gmail app.
I am currently using Gmail as my primary email client as it provided the best and top-rated security.
Due to which I have no other further interest. However, MS Outlook is also nice to use as it manages all the tasks easily but with the con that every time and then I experience some error related to it. But for work I keep MS Outlook. For other refernces i prefer Gmail Inbox.
Apart from all two which I have discussed, I ended up using Edison as I have the preferences which manage all my email accounts with this client.
All the well known products work well for me. As a G Suite and Microsoft Cloud administrator more and more I prefer Microsoft. You get the biggest feature set and superb support. The enterprise grade email starts at $5 a month retail.
I noticed this stat in the recent earnings call news. There are 200,000,000+ daily users of the work and school account type now. They maintain their high up time and fast quality support. I'll be moving another domain I use to the Microsoft cloud because it costs less and works so well among the 3 main vendors I use.