Flutter vs swiftui – transparency
If you are curious about the differences between creating views in Flutter vs Swiftui, I recommend checking out the experiment in which the SwiftUI sample application was recreated in Flutter at WWDC 2019. The results were very similar, but thanks to Flutter’s relative maturity, writing code is a bit faster. On the other hand, SwiftUI will undoubtedly be easier for an iOS developer than using Dart, the language created by Google and on which Flutter is based. In my opinion, SwiftUI is definitely cleaner than Flutter, mainly because it was designed exclusively for iOS devices. Flutter, built to support both iOS and Android, needs more code to achieve the same goals.
Both solutions in terms of maturity
Considering Flutter vs Swiftui, it should be mentioned that Flutter is more mature than SwiftUI. This can be seen (in terms of building views) in allowing developers to use multiple ways to achieve the same goals. On the other hand, SwiftUI currently has far fewer view-building solutions. That is sure to change in the future, but for now, if you want to build more complex applications, a better way is to use Flutter (or stick with Storyboards in Xcode – but that’s another story). All in all, being a tool made for cross-platform development, Flutter will always have more ways to build complex views.