I'm genuinely curious which feature(s) of node you like better than ASP.NET. I have used both and find them quite similar as far as "raw" capability. ASP.NET however has all of the things you were asking for: great Intellisense, great tooling (for instance integration with Entity Framework), great libraries available (such as SignalR), code in C# or any .NET language (including F#), rich async support...
I like node too, but to me, the reason to choose it is either if you want to remain platform-neutral, or if you really like Javascript.
I would imagine he's referring to the non-blocking IO and evented model. ASP.Net and friends use threads for everything, which allows for heavier processing, but also is more restrictive in terms of concurrency.
I like node too, but to me, the reason to choose it is either if you want to remain platform-neutral, or if you really like Javascript.