I've done some web dev with node, python (GAE) and php. I ended up using C# + mono's web server for a recent project and was pleasantly surprised.
ASP.net is showing its age but there are some solid libraries, reasonably comprehensive documentation, and some nice new frameworks like MVC out there to use (I didn't even use a framework, just wrote 500 lines of wrapper logic so I could expose some REST services that handled JSON input/output and then built a connection pool for my Redis connections). If you know C# (or another .NET language) well enough, you can lean heavily on the type system and write automated tests for everything else and get all your errors/red tests displayed to you in your IDE. I hit very few runtime errors while building the services.
It's also pleasantly surprising how easy ASP.net deploys seem to be: rsync your app folder to the web server; the app.config and bin/ folders inside ensure that all your dependencies and configuration move over to the target machine. Mono's ASP.net server seems to support almost everything Microsoft's does, so I think I only ran into one behavioral difference (and it was documented, albeit a little hard to find).
ASP.net also has some of those same code reuse benefits you get with node.js, just in a different direction. Now if you have any native C# applications or libraries for doing interesting things, you can expose them as a web service trivially. JSIL's online sandbox (http://jsil.org/try) is literally just the compiler libraries deployed to a linux box with a 100-line shim over them that does compilation and caching and error reporting.
ASP.net is showing its age but there are some solid libraries, reasonably comprehensive documentation, and some nice new frameworks like MVC out there to use (I didn't even use a framework, just wrote 500 lines of wrapper logic so I could expose some REST services that handled JSON input/output and then built a connection pool for my Redis connections). If you know C# (or another .NET language) well enough, you can lean heavily on the type system and write automated tests for everything else and get all your errors/red tests displayed to you in your IDE. I hit very few runtime errors while building the services.
It's also pleasantly surprising how easy ASP.net deploys seem to be: rsync your app folder to the web server; the app.config and bin/ folders inside ensure that all your dependencies and configuration move over to the target machine. Mono's ASP.net server seems to support almost everything Microsoft's does, so I think I only ran into one behavioral difference (and it was documented, albeit a little hard to find).
ASP.net also has some of those same code reuse benefits you get with node.js, just in a different direction. Now if you have any native C# applications or libraries for doing interesting things, you can expose them as a web service trivially. JSIL's online sandbox (http://jsil.org/try) is literally just the compiler libraries deployed to a linux box with a 100-line shim over them that does compilation and caching and error reporting.