When comparing Flutter vs Appcelerator Titanium, the Slant community recommends Flutter for most people. In the question“What are the best frameworks for developing cross-platform mobile apps?” Flutter is ranked 1st while Appcelerator Titanium is ranked 12th.
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 Provides a native experience
Through using Titanium's API and UI components similar to that of the platform's native UI, Titanium provides a native experience.
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.