Superhuman Mail is completely keyboard first and the team has put in so much more thought into the experience. You can switch Inbox Splits without thinking and simply hitting tab on your keyboard. You're in a FLOW.
Snoozing and scheduling in Superhuman Mail is extremely fast. You can write in natural language and even remind you or schedule to send in another time zone. This feature is SO HELPFUL and used SO OFTEN because they make it easy.
Superhuman Mail even allows for Smart Send, which sends your email based on when someone is most likely to open it. It takes into account time zones, business hours, and individual habits (like if someone tends check their emails more in the mornings or night).
You can also schedule an email later into the future and set to send "if no reply" or "regardless" saving you from embarrassing mistakes... unlike the other tools which only allow you to send emails regardless so if someone replies, your email is still going out, yikes!
Replying to emails in-line in Superhuman Mail is easy. Simply highlight the text you want to reply to and hit enter... and it's done. We're talking about seconds and it does not break your flow. Superhuman Mail encourages you to quote others and reference other threads which allows you to give more comprehensive and thoughtful replies. When you want reference your thread or another email while replying, you can easily pop out the compose screen with shift + enter, and you'll notice how it actually makes room for the email thread to easily reference.
In terms of Snippets, you hit the semi-colon on your keyboard and they appear. You can save default to, cc, bcc fields. Superhuman Mail goes further and gives you analytics for their snippets — aka seeing the number of times you sent the snippet and the % of opens and replies, which is incredibly helpful if you're using them often for something like sales.
Superhuman Mail's offline mode is awesome. We can't say how many times we've lost internet and not even noticed with Superhuman Mail. It has super fast offline search, and you can compose, snooze, archive, and schedule emails offline.