Intravert is built on top of Cassandra. It is not a fork. Rather, it is a plugin which augments (or replaces - up to you) the default CQL and Thrift transports.
Game Changer Features
Intravert is more then an RPC library, query language, or transport for Cassandra. IntraVert gives access to new powerful ways of working with Cassandra.
Multiple variations on server side processing allowing users to perform arbitary programatic transformations on the server side before the results are return to the client.
GETREF feature can be used to execute procedure and join like logic in a single RPC request.
A simple sync/async API and Transport that runs over HTTP allows clients to chose from JSON, JSON compressed by smile, and even big fat sexy XML.
No more dealing with byte or ByteBuffers. Intravert lets users work with simple familiar objects like String or Integer. See Types and Composites.
From an application standpoint, if you can't do sparse, wide rows, you break compatibility with 90% of Cassandra applications. So that rules out almost everything; if you can't provide the same data model, you're creating fragmentation, not pluggability.
Intravert was conceived of and designed by long time users of Cassandra who have written numerous real-world applications built on the existing Thrift API.
This API had it's warts for sure, but it was felt among us that the direction of the Cassandra project with regards to the introduction of CQL sidestepped some of the core reasons we chose Cassandra in the first place.
Therefore, Intravert is a new approach designed to leverage what we've learned down in the trenches writing and deploying applications which use Cassandra. Intravert is not intended as a fork, thumb in the eye, or any other detrimental action to the Cassandra community or commercial vendors around such. It is simply a purpose built tool to facilitate GettingShitDone™ with real world applications.
Spend some time looking through the documentation, test cases, and examples to see if this approach makes sense for your architecture.
You can find a brief overview located here: https://github.com/zznate/intravert-ug/wiki