I have developed a JSON type for SQL Server available for purchase at http://www.json4sql.com. It is a port of the binary JSON type just released for PostgreSQL.

It also offers:

* Table value functions for returning elements of JSON objects / columns as a result set

* A fluent API for creating, modifying, and accessing object properties

* JSONPath expressions to set, remove, and get data within JSON objects (similar to XPath expressions for XML)

* Aggregations for converting result sets into objects or arrays

* Binary storage for fast data access without reparsing