What have you been using before?
The only thing I can come up with us Microsoft's history of embrace, extend, extinguish and all that. Like how VS Code plugins have a bunch of licensing conditions around them, to the point where they don't run in VS Codium (I use Rider, but a friend had some problems with that).
In general, .NET feels like a more focused Java - ASP.NET is more consistently put together, EF is arguably easier to use than JPA/Hibernate and there's lots of nice integrations (though maybe the AutoMapper thing sucks more than MapStruct). The ecosystem feels smaller and more niche than Java's, which isn't a good thing, but at least what's there is good, in addition to the language being popular in game dev or interactive demos.
It runs on Linux too, the SDK is simple to install and has no issues with containers, it's okay from performance to language features (and even F# exists for those who like that sort of thing).
It's easily in my top 10 for productivity. The other spots might belong to Python/Django, Ruby/Rails or even PHP/Laravel and Node/Express, in addition to Java/Spring Boot or maybe Dropwizard. Not sure about the exact order, but it's not like it matters.
Personally, love their products. One of the only products I will happily pay for. Had to unfortunately deep dive into the C# and .net world for a bit and Rider IDE made the process less painful than it would be with VS code or visual studio.