After testing many clients I learnt to stop worrying and just use Mail app.
Last week I searched for an email in Mail.app. It was right there on the screen and it couldn’t find it. It also fails to display or even list some attachments.
This is unacceptable to me. Yet I keep using it because I dislike Gmail’s web interface and my Vim imap setup is not really usable yet and probably never will be.
I'm here too.
I've used many, many different clients over the last few decades (yes, including Linux `mail`). I have to use Outlook at work, and I have to use my providers' web clients on my Windows gaming PC, but on all my other devices I use Mail.app.
I just... don't ever use all the features of the other clients, or don't like some of the behavior they have, or any of that. For a long time I would get excited about new email clients and try them out right away, but no more.
I dunno if it's just that I'm getting old, or if I just don't care as much, or both, or something else.
Indeed, I'm additionally using https://mimestream.com for company Gmail as the Gmail support in Mail.app is sometimes a bit lacking (Labels etc.), but it's also a good way to keep private and work emails separated.
I feel you. I now just use email in my web browser via the respective providers recommended website, aka mail.google.com, microsoft.office365.exchange.email or whatever it is they are calling it these days.
MailMate did that for me.
I just wish that Mail.app would have a seamless ingegration with Calendar.app like Microsoft already provides with Outlook. Also the label system feels very outdated compared to Outlook.
Kanmail turns your Gmail labels to a columnar kanboard, pretty useful in wide screens https://kanmail.io/
Mail causes me to procrastinate so much, and I have no idea why. I use icloud everything, so I wanted my mail there as well, but after 12-13 months I switched back to FastMail because their UX is subtly better suited to quickly sorting through mail for me. And fwiw I'm afaik not using any FastMail features that Mail doesn't have.
I don't mean this in the way that Client A > Client B, but I have spent a fair amount of thought on this, and I have not been aple to pinpoint exactly what characteristics makes the difference for me, which I find to be interesting in itself.