When comparing Opera Mail vs Microsoft Outlook, the Slant community recommends Opera Mail for most people. In the question“What are the best e-mail clients for macOS?” Opera Mail is ranked 8th while Microsoft Outlook is ranked 17th.
Ranked in these QuestionsQuestion Ranking
Pro Opera Mail CAN BE set as default email client in Windows 8 & 10
Pro Automagic smart filtering
After a bit of use Opera learns what e-mail belongs in what folder just by previous usage. This makes for a convenient way to have e-mails filtered without having to manually mange every e-mail.
Pro Free and based on Mozilla code
Opera Mail is completely free to download and use and it is based on Mozilla's code, which is what makes it a bit similar to Thunderbird in looks and function.
Pro Intuitive user interface
The design of the UI in Opera Mail is clean and intuitive, making for an easy to use client.
Pro Integrates with cloud storage services
Microsoft Outlook comes with built-in cloud storage browser allowing you to attach files directly from services such as Dropbox, Box, Google Drive or OneDrive to emails and directly open attached files without the need for the main cloud storage app.
Pro Good built-in calendar
The calendar includes agenda, day and three-day views.
Pro Quick swipe features
Microsoft Outlook comes with quick swipe features where users can quickly swipe the thread either from left (to schedule) or right (to delete or archive). Additionally, users can also customize the swipe actions to, for example, set swipe from left to archive or swipe from right to delete.
Pro Excellent notifications center calendar widget
Pro Good built-in contacts
In addition to showing contact information, the People section of Outlook can show all conversations you've had with a person. Moreover, if you're looking for someone that's not in your contact's list, but is in your company's or school's directory, Outlook can pull that information through integration with Global Address List (GAL).
Pro Helps prioritize email
The app will automatically attempt to figure out which emails are important to you and surface those. The priority emails will show up in your inbox in a tab called Focused, with other emails in a tab called Other. It aims to separate spam and promotional emails from the important emails.
Pro Integrates with Microsoft services
Con Very limited feature set
Compared to Thunderbird.
Con Does not support 4K monitors
Con Sync is slow
Opera tends to be slower on e-mail sync when compared to other popular clients.
Con Doesn't follow security guidelines
The app stores user information and credentials on outside servers which is a violation of ActiveSync password requirement policies. These security concerns have been enough of an issue that European Parliament has banned its members from using the app out of fear that it might lead to leaking sensitive information.