Main difference is that Stride is entirely written in C#. So if you are a .NET developer, the technology is transparent.
Other game engines just use "C# scripting" with their own runtime and c++ engine core. So it is a black box, as supposed to Stride that is completely open and the engine and the scripts are normal C# with latest official .NET runtime.
Right now it looks like:
- Unity: Stride is more modern (C# 9) and hopefully less buggy. Also open-source
- Godot: Stride is more traditional as it uses C# instead of a custom language. It also looks more polished but i can't say anything about that from just the screenshots
- Unreal: Stride uses C# which is higher-level than C++, and it's open-source, yet just like Unreal it looks really good
But the devs should put the actual comparisons on their website because they're very important.