JSON4SQL will run on all SQL Server 2012 and 2014 versions.
JSON4SQL stores JSON in a binary format ported from the JSONB format used in the PostgreSQL database. A description of the JSONB type can be found here and in the PostgreSQL documentation here. JSON4SQL is a port of the PostgreSQL implementation to managed C# from PostgreSQL 9.4 released in December 2014.
Although we have not released official benchmarks of JSON4SQL's performance, in the extensive test cases run to date, JSON4SQL performed approximately 20% faster and was 20% smaller than the same complex queries and data stored using SQL Server's XML data type. More definitive benchmarking will be coming soon.
We have contemplated developing an unmanaged version of JSON4SQL for increased performance, but currently we only offer a managed version because of the limitations placed on running unmanaged assemblies by many database administrators. This comes at a performance cost for some functionality, but also ensures the type is safe and self contained so as not to disrupt the proper functioning of the database or create security issues.
JSONPath is a JSON equivalent to XPath for XML. It is based on this article by Stefan Goessner. The result is a powerful query language for extracting subsets of the data stored in a JSON typed field. It supports paths to reference data within the JSON structure as well as recursive descent, wild cards, array operators, and filtering.
No, JSON4SQL is completely contained within a single small DLL and installation is as straightforward as enabling the CLR on your database and loading the assembly.
Yes, a 30 day time limited trial version is available here