I'm also primarily a .NET dev, using ASP.NET MVC. But for my most recent project I used node, and I'm hooked. Probably because it allowed me to take existing JS knowledge and apply it, but still. ASP.NET MVC just feels too heavyweight afterwards.
That said, whenever using something other than C# I miss LINQ. It's awesome.
I've been working a lot with node lately as well, there are some things I like but some I miss so much from C# ... there is nothing anywhere near as good as VS for node, and god I miss ReSharper and compilation errors.
I'll admit it. Losing that is a bit scary in some ways. It does lead to some laziness though. But sometimes it's awesome to remove a property from an object and have the compiler tell you all the places that are broken now.
On a similar note. I've followed your Playtomic blog a bit and it helped me make the jump to MongoDB for our gamification platform. (We still use SqlServer for lots of things though) Here's to trying new types of kool-aid! :)
I had the same frustration, until I finally broke down and just fed my JS through jshint (http://www.jshint.com/). Keep a JS console open while developing and have it display relevant parts of the returned object you care about.
Unfortunately there's no reSharper for JS but eh... I feel like it's not as necessary with JS as its a fundamentally simpler language than C#.
That said, whenever using something other than C# I miss LINQ. It's awesome.