I get your nervousness about google in general. I really like flutter from a UI framework. The buildcontext and widget paradigms are awesome. And when you combine bloc, it just feels so good, architecturally.

As for pub.dev, my most recent frustration is with google deciding to just walk away from their charting package. It was great, imo. But of course they just abandoned it. What a huge pain in the butt. And as a very seasoned app architect, you have to know the dangers of using "packages". Do they really give you the long-term velocity you are looking for? Do they ultimately become a hindrance? How much architectural debt are you taking on to move quickly at first?

From a language perspective, having learned .net C# a long time ago, Dart is awesome. Dart feels like it is the right amount of functional and the right amount of object oriented. It just brings in all the LINQ concepts as a natural part of the language.

But when you get into it, flutter is not really a great cross-platform framework. I say that because of the whole Material theming and the mess you have to create if you choose to build an app specifically using Cupertino or Material components. I get that google is doing their best here, and it takes two to tango, so to speak. Apple is clearly not doing anything to make cross-platform development easier. So at least google is trying to make this better.

My last concern is you still have to dig in and understand all the uniqueness of building an iOS or Android app from a build perspective. So flutter doesn't really help you there either.