As a previous strong competitor to Outlook, Lotus Notes also provides rich features, says emails, calendars, to-do list, contacts, discussion forum, sharing file, etc. However, Lotus Notes gives up ease of use and compatibility for the sake of security, says Lotus Notes does not allow the multitasking facility, an restricts users to work with one account at a time. In addition, Lotus Notes users pay more for buying email applications separately and high maintenance cost. Comparing to Lotus Notes, Outlook is much easier to use with its simple UI and self-narrative features, but Lotus notes requires technical capabilities.

Lotus Notes supports multiple OS, for example Mac OS, Linux and windows, while Outlook works in Windows OS (users need to install Microsoft Outlook for Mac to work in Mac OS). Nonetheless, Outlook wins most part of corporate market.

As mobile devices come out and get popular, more and more people turn to work with mobile phone, tablet, and laptop and so on. Work online is the trend. Google Apps provides dozens of applications to help you work online, such as Gmail, Contacts, Calendars, Tasks, Keep (Notes and Lists), Drive, etc. Google Apps cover almost all parts of Outlook features online.

Microsoft has recognized the trend and thread, and released Office 365 (including Outlook), Outlook.com, OWA to respond to the situation. Ignoring the Outlook desktop application, Google Apps, Outlook.com and Office 365 work well online.

The Windows Mail is a free Email client provided since Windows Vista (it’s absence in Windows 7). It is the successor of Outlook Express, and works similarly as Microsoft Outlook with pretty background image. It also contains Emails, Calendar, People, To-do List, .etc. Multiple email account types are supported. If you have not got Microsoft Office suite or Microsoft Outlook yet, Windows Mail will be one of the best alternatives.

Mailbird is a desktop email client working in Windows OS. With it, we can easily sync our email accounts in multiple custom layouts. Although Mailbird is an email application, its App integrations feature gives us a change to connect most of our favorite emails, calendars, tasks, and other social-network apps into one, such as Google Calendar, Facebook, WeChat, and more.