When comparing GyazMail vs Opera Mail, the Slant community recommends GyazMail for most people. In the question“What are the best e-mail clients for macOS?” GyazMail is ranked 6th while Opera Mail is ranked 11th. The most important reason people chose GyazMail is:
Goichi Hirakawa, the main developer of GyazMail, has been committed to his project since 2003 and delivers updates regularly.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Long term support and development
Goichi Hirakawa, the main developer of GyazMail, has been committed to his project since 2003 and delivers updates regularly.
Pro Mail sorting rules
The user can define complex mail sorting rules for incoming and outgoing mail.
Pro 64-bit support
As of v1.6
Pro Native Cocoa API based
GyazMail is a native macOS application, based on the Cocoa API.
Pro customizable fonts & colors
the mailbox view is very comfortable
Pro Very good support for Asian languages
GyazMail is a Japanese product, so it has very good support for Asian languages.
Pro Supports older versions of macOS
GyazMail is available for all versions of Mac OS X / macOS starting with version 10.1
Pro Freely selectable hard line wrap
In GyazMail you can set a maximum number of characters per line. The program will wrap the lines using hard wrapping on sending. This feature is very useful for newsgroups that require a hard break after 72 characters.
Pro Supports a big variety of character encodings
Uses Oniguruma regular expression library, which is a very elaborate regular expression engine that supports a big variety of character encodings. This makes very much sense with e-mail, as in an e-mail theoretically any character encoding could be used. Because it is free software (BSD), written in C, very elaborate, stable and still actively maintained it is also used in Atom, Take Command Console, Tera Term, TextMate, Sublime Text, SubEthaEdit, and jq.
Pro Intuitive user interface
The design of the UI in Opera Mail is clean and intuitive, making for an easy to use client.
Pro Very efficient search
Be it the subject or the sender, it is very fast and accurate.
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.
Cons
Con Looks old and outdated
Con If connection drops or times out, Gyazmail just sits there until you click OK button
Con Cannot remove attachments to save space
Con Still a 32-Bit app
Con Being discontinued
Opera Mail will be end of lifed per Opera website
Con Very limited feature set
Compared to Thunderbird.
Con Sync is slow
Opera tends to be slower on e-mail sync when compared to other popular clients.