The languages are very different. C# has much more powerful abstractions and is a much larger language in general. That is both an advantage and a disadvantage. Modern C# is also very fast, I wouldn't bet on Go winning that comparison.
My experience with Go is a while back, before it got generics. While I liked the overall idea of a language with little syntax and a focus on simplicity, I didn't really like Go in the end. It was a weird mix of too low-level and high level code. It exposed low level details that I don't need to think about in C#, and it is missing convenient abstractions like LINQ.
Personally, I like async/await in C# more than Go concurrency. I know this is heretical here, but I don't care about function coloring or any of the abstract advantages of other concurrency approaches. Async/Await in C# works for me (in non-legacy code) and is easy to understand.
the main problem with the .net async/await is the immediate execution of a call returning a Task, without control over where it may execute. F#'s asnyc was way saner and easier to understand in my opinion.
I'd beg to differ on the easy to understand... last time i worked with this stuff like ConfigureAwait only has cargo cults and no real good explanation, and wasn't covered in any recent version of eg. CLR via C#... Distributed tracing and thread management were totally bitten by async, also the way iterators and LINQ were broken... that was when I got off the train, as it broke the best abstractions for line of business code so that instead of designing an IO pipeline lazy developers could simple put Task.Run around blocking IO calls at the bottom of the codebas, and ... yeah, we are back at function coloring.
This brings me to: I winder for what kind of apps did you find it a delight, because for extensive data wrangling leveraging multiple calls it was a pain.
You don't need ConfigureAwait() at all in modern C# (unless you're writing desktop UI code, I don't know enough about that to comment there). In a modern ASP.NET Core web application you don't care about which thread your Task executes, there is no synchronization context at all.
I'm using C# for the backend of a web application, not legacy but .NET Core from the start.
Modern .net is surprisingly performant while also being very high level if needed. So it is very close to being a "learn once" ecosystem. This means you use it to write code for a much broader range of usecases than others, you will have a broader / more mature ecosystem than others, and your potential hiring market is more vast.
Go is not much more efficient, compared to NativeAOT - though it can be faster in some areas. The big reason why someone would want to use C# is that it's a more expressive language. You can even write your DB queries with LINQ (C# lets you express code as data), making them type-safe.
Go isn't as much fun. And is usually slower for my work until I bump up the GC and then it uses roughly the same amount of memory.
I have also found c# async to be lighter than go's concurrency story, and dotnet11 is going to make that much more clear.
Now: I write software for fun, not for money.
So for a requirement where both golang and .net would suffice, would you choose .Net over golang?
Yes. Unless I really need CSP, but then I would much rather use f#+hopac because CML is the bee's knees.
For general concurrency where async doesn't suffice, go is nicer than C#, but hopac is nicer than go.
If go had proper concurrentML I am pretty sure I would use go a lot more. Again: this is for hobby projects where I get to choose freely.
I know it's not quite as important in the agentic world, but the .NET tooling (across Visual Studio, JetBrains Rider, and C# Dev Kit for VS Code) is just awesome. Some people might frown upon full-blown IDEs, but sometimes they're just incredibly handy.
Even the non-visual stuff is pretty awesome, claude is able to trace and profile .NET code without skills or MCPs.
The tooling and development UX.
Put things like their remote debugging experiences side-by-side and you will quickly learn why some of us go for the Microsoft tools rather than the others.
That is an urban myth, CLR was designed with support for C++ in mind.
Also Go is at the stage of C# .NET 2.0, and still plenty of lacking language features.
I really think the creator of C# made a disservice to the .NET community by picking Go for the Typescript rewrite.
Compare the ecosystems of .NET vs golang. No comparison whatsover. IoT, mobile, web (front and backend), cloud, etc. I think Go lacks variety and is more focused on traditional greybeard areas.
At former jobs, because people know it and switching from .Net <-> Go generally isn't worth the time to learn other language.
Sure, having a runtime is downside but difference in container size for your average CRUD App doesn't really matter. Performance IME is very similar.
Ops type here.
Native interop is much better in .NET, that matters a lot for some systems.
What's go's equivalent of LINQ?
In addition to what the others have said, I also enjoy the extremely robust ringtone reflection system in .NET. I don't know of any other systems that provide more complete detail. Maybe Java, though it's been a while since I've used it. It makes reflection in other languages feel prehistoricaly primitive.