System components is not a thing on Android. You've not seen the default EditTexts in years. Material, which you'd consider the default is a library, whether in XML or Compose (and Compose is a reimplementation of them).
Also, Android has never pushed for unification of UIs. Use Material if you want because it's an alright design system, or write yours entirely from scratch.
React Native & Flutter look... Exactly how you want them to look. Unless there's a bug in Flutter's Material implementation, it'll be the same.
I'm iOS dev but right now learning flutter. Few observations:
1) Difference between new latest Material You (aka material 3.0) and SwiftUI is smaller than Material 2.0 and UIKit - at least regarding look & feel.
2) I find old UIKit style quite boring same with older material 2.0. On the other hand SwiftUI and Material 3.0 looks more modern. There is rarely any iOS app that use native widgets without completely changing branding and styling.
3) Comparing to SwiftUI, new Material 3.0 feels more complete - there is more widgets and navigation choices. UIKit and SwiftUI is lacking in widget departments regarding: snackbar, bottom sheet, modal bottom sheet, navigation drawer, navigation rail, modal navigation drawer, cards, multiple dialog options.
I recommend to checkout and play with material 3.0 demo (just keep in mind this is web version- you will have even better experience when using native compiled version on mobile or desktop - web version of flutter could be better):
I tried both macos flutter gallery and on iOS and surpassingly is pretty good these days and smooth and feel native - even text selection works these days, moving cursor with long press on keyboard space etc. Occasionally was more difficult to dismiss keyboard on iOS and back/next mouse keys or touchpad gestures didn't work on macOS flutter gallery. But overall I'm quite satisfied and surprised comparing how it looked 4 years ago.
I had high hopes for this new renderer, but it’s still not good enough. There’s a single frame lag when scrolling, it might not be noticeable to some people, but I do notice and it’s very annoying. There’s an issue opened: https://github.com/flutter/flutter/issues/110431
Sort of. It adds a lot of layers on top of the core components and isn't just vanilla native UI plus some tweaks. React Native apps still stick out compared to real native apps unless you put in a fair amount of extra work.
In my experience RN apps are most obviously “un-native” feeling in their navigation, which is where the most custom-rolled code seems to be. It often feels clunky, with weird transitions and foreign behaviors.
