I assume that you mean Flutter by Dart. I have over 6 years experience programming in Android SDK, but about 1,5 month in Flutter. So far I think that Flutter is the future for mobile development. Flutter SDK is much better designed. Ecosystem of libraries seems having much higher quality. I would even say that android opensource libs are having really poor quality. Many times I am wondering how can garbage like that have so many stars at GitHub. Android SDK is hard to compose so you reinvent even basic things on and on, which is totally different story at Flutter. Lolcycle? Both are having good documentation. I quess apps in Flutter can be done in 1/3 of time compared to develop AndroidSDK and iOS, its design is that much better and contemporary. As of language comparison - Kotlin is better, but the difference is not that important. Go from one language to other is no problem. Dart is being updated with new features.

I've selected Flutter and Dart for my side projects and never regretted. Dart learning curve is easy after any OOP language . Flutter as a framework is also has a low entry threshold. I've already started development after a week of learning. Pros for me: code can be build for Android and IOS devices (for ios you need mac or VM), apps written in Dart have great performance on each of these platforms, flexibility. Cons: if you want to build a product as a business and want to hire a new Flutter Developer in the future it can be a problem as the framework and language is not popular for the moment.