When comparing Mozilla Thunderbird vs GyazMail, the Slant community recommends Mozilla Thunderbird for most people. In the question“What are the best e-mail clients for macOS?” Mozilla Thunderbird is ranked 2nd while GyazMail is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Pro Free (as in freedom and beer)
Pro Good filtering system
Mozilla Thunderbird offers a flexible filtering system with the ability to set flags and read/unread, as well as sort/assign to new mail directories. There are also numerous plugins available to assist in the filtering.
Pro Very reliable
Version after version, Mozilla Thunderbird works as expected.
Pro Lightning Calendar and Address Book integration
Pro Large assortment of plugins available
Mozilla Thunderbird offers a huge amount of extensions to expand the usability and options of the client.
Pro Available on Linux, OS X and Windows
Pro Consistent and involving a moderate learning curve
The app design of Mozilla Thunderbird has not changed significantly since its beginning, making its learning curve almost non-existent.
Pro Great flexibility
More options and extended settings than most power users could dream of. Get it working how YOU want.
Pro Tabs for navigation
Pro Send large files easy
Install pCloud plugin for Thunderbird and your files (upto 20 GB free storage included) will be received as download links
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 Native Cocoa API based
GyazMail is a native macOS application, based on the Cocoa API.
Pro Mail sorting rules
The user can define complex mail sorting rules for incoming and outgoing mail.
Pro customizable fonts & colors
the mailbox view is very comfortable
Pro 64-bit support
As of v1.6
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.
Con Terrible integration with macOS
Simple things - drag/dropping pictures doesn't work, for instance.
Con Outdated interface
Thunderbird's interface is very outdated and unpleasant. It feels more like a Windows XP application than like a modern MacOS one.
Con Serious bugs
Clicking on a subject line can bring up the wrong email.
Con Development slowed to only focus on stability and security
Mozilla Thunderbird has slowed down its development of features to only focus resources on security and stability.
Con Subject lines can (temporarily) disappear from the list
This is sporadic behavior.