I did a short evaluation a while back (while support for desktop/web was still in beta so much has probably changed), ended up going the PWA route. Developer experience was fantastic, code completion/debugging/documentation/compiling were all great and smooth experiences, Dart was easy to pick up quickly although some of the code generation stuff such as serialisation/deserialisation was a bit clunky. However the deciding factor at the time was that the end result felt very much like a mobile app forced into a desktop environment, things that users expected to have like copy+paste weren't there, keyboard shortcuts that users took for granted were a hassle to reimplement, the scrolling felt 'off' in a desktop environment and performance wise it could feel stuttery quite often.
I quite like the fundamental ideas behind Flutter (a lightweight GUI runtime that can produce consistent results across many platforms) so hoping these are already or on their way to being ironed out
I've evaluated both Tauri and Flutter + flutter_rust_bridge.
I immediately felt really productive in Tauri/Svelte/rust. It just kind of clicked with me (completely new to Svelte, but been doing SPAs and JS desktop apps for some time as well as being in the rust scene for years). It was like the ease of electron, but with a better build framework for bundling rust. Really a good setup, easy to get into, easy and fast to build in.
I think Flutter is a really great UI framework. The way it's set up really makes sense and makes it fairly easy to structure the UI. That said, I really do not like Dart at all. I found it difficult to learn a new language and a new UI framework at the same time, and found myself pining for HTML/javascript again. flutter_rust_bridge obviously alleviated this a bit because it made it possible to move most of the logic into rust. I am honestly also worried about Flutter being a Google project. They tend to abandon projects quite a bit. I do like the promises of Flutter and didn't actually have any material issues with it. I think I might give it another go on the next app I build and see if I can get over the Dart hump.
Flutter is really compelling, would love to be given a project using it based on what I've seen of the environment and tooling. Dart is nice too. In my recent evaluation though I decided to go with PWAs unless I really need native only APIs. Modern web APIs are decreasing the argument for native.
