What is Superhuman?
Superhuman is an email client. It bills itself as "the fastest email experience ever made", and it may well be, with its ⌘-K Superhuman shortcut to move nearly every part of email manipulation to the keyboard, and its heavy reliance on local caching to speed up the search and retrieval experience. The learning curve is steep and the price point ($29/month) is high, but many customers point to productivity gains to justify the price.
Superhuman is a layer on top of Gmail, and provides a cohesive design experience in several features and functions that are typically provided by discreet services or extensions. These include: Triage. Undo send. Insights from social networks. Follow-up reminders, Scheduled messages, and read statuses. And more.
According to Capiche user @chrismessina: "Superhuman is so fast, delightful, and intelligent — you'll feel like you have superpowers."
Superhuman is best for professionals who spend a significant amount of time using email.