When comparing Flutter vs Fyne, the Slant community recommends Flutter for most people. In the question“What are the best cross-platform GUI toolkits?” Flutter is ranked 15th while Fyne is ranked 24th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open source
Pro Great developer tools debug/hotreload/analyser
Pro Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers.
Pro A single codebase for iOS AND Android
Pro Fast
The developer's goal is to allow people to make apps running at 120 FPS.
Pro Mobile support
Android and iOS are supported.
Pro Easy to learn
Simple and consistent API.
Pro Permissively licensed
Fyne is licensed under the 3-clause BSD license, which has fairly lax restrictions on usage.
Cons
Con Still in development
According to the website, Flutter is still in its early stages of development.
Con Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers. BUT if you have to learn it ... it's a con.
Con Dart is unpopular and never gained serious community traction like Kotlin or Java
Con Does not support 32-bit iOS devices
If you plan on targeting iPhone 5, 5C or earlier, you can forget about Flutter.
Con Google has a bad history with product loyalty
Con Go specific
Fyne is only usable in Go applications.