When comparing Galaxy vs Flutter, the Slant community recommends Flutter for most people. In the question“What is the best CSS framework?” Flutter is ranked 25th while Galaxy is ranked 43rd.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Fast and lightweight
Galaxy uses CSS animations and rarely relies on Javascript (2kb). It's about 1/67th the size of Bootstrap.
Pro Beautiful
More modern UI than traditional frameworks like Bootstrap.
Pro Semantic markup
Using the custom attribute g, it's very easy to scale and maintain.
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.
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.