I recommend that you write a blog post on this topic, and try to support your assertions with formal evidence and citations. When you're done, post a link to your blog post on Hacker News.

I must admit inbox by gmail is so good I am never going to need to use a mail client on any computer ever again.

If you havent tried it give it a try. Its workflow is different and until you get used to it you wont appreciate it.

There are various competitors already and every few months or so another one seems to crop up.

The reason I keep using Apple Mail is that those competitors for the most part don't offer these features (at least to my knowledge there's not a single competing solution out there that supports all of them):

- non-GMail accounts (Exchange, standard IMAP etc.)

- email encryption

- multiple signatures for multiple accounts

You're referring to the Mail app on the Mac, correct? I have two email accounts, gmail and icloud. Mail seems to handle them both very well in OS X, except for Search on the gmail server.

The alternative is gmail, either the native app or web version. Case closed. Nothing to see here.

Using Airmail since long instead of the stock mail app. Could not be happier.