When comparing Flutter vs Dash, the Slant community recommends Flutter for most people. In the question“What are the best offline documentation browsers?” Flutter is ranked 1st while Dash is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
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
The developer's goal is to allow people to make apps running at 120 FPS.
Pro Easy docsets download
Download docsets from CocoaDocs.org, RubyGems.org, Maven.org (Java and Scala), Packagist.org (PHP) and GoDoc.org.
Pro Supports docsets generated using Doxygen
Pro Great fast documentation lookup
Has a handy sublime plugin. Press CTRL-H and it jumps straight to the docs for that object.
Pro Integrates well with a good selection of apps
They provide very useful integration with apps that are very fitting with using Dash's features. Once integrated, you can really get the feel for being a must have part of the app its integrating with.
Pro Great utility app to use for snippets
Snippet apps come in various forms, such as basic snippet (text) containers and added features with text / keyboard utilities to name a couple. This app not only includes this feature, but takes it a bit further than most by adding unique ways to further customize this practice to your own preference.
Pro Easy to create new docsets in case there isn't one that exits already
Gives plenty of guides and information on how to generate a docset.
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 Forced wait time to view docs
If you use the free version you are very often forced to wait 10 seconds to view something you've chosen to look at. If you change apps or lose focus of Dash, it'll start that 10 second timer over again. A real crappy thing to do to your users in order to get them to buy it. Forcing you to waste your time.