In my opinion, you can go a bit more low level in C# and have control over allocations, data copying, threads, etc. Also, .NET is a bit more general purpose than Node. If the workload is more about computation (CPU/GPU intensive stuff) or has some unusual technical requirements (uncommon protocols, interop, etc.), you can really benefit from being lower level and more generic.
But all this is very project specific... it's hard to make these sort of claims about performance.
But all this is very project specific... it's hard to make these sort of claims about performance.