I actually think this says something interesting about .NET v.s. open source platforms. The new batch of NoSQL products are being developed almost exclusively in the open source world - they're written to run on *nix (Windows support, if it exists at all, is generally an after thought) and the client libraries that ship with them target the open source languages first. In this particular case, it feels like closed-source platforms are second class citizens.

I'll hazard a guess that one reason for this is that NoSQL systems are mainly designed for scalability, and free operating systems are significantly cheaper to scale than platforms with a license fee per node.