What are some alternatives?
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Front App - multi-channel inbox service for collaborative teams
eM Client - eM Client is a Windows-based email client for sending and receiving emails, and managing calendars, contacts and tasks.
Slack for Mobile - Rebuilt from the ground up
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Gmelius - Gmelius turns Gmail into your team’s workspace, to manage clients & projects within your inbox.