I'm using JSON .Net asset from the asset store as it provides the best implementation compared to JSON .Net free DLL. It works perfectly fine and I'm already working on custom converters to handle data properly (my PM action can filter to or exclude object properties as well). So far I've JSON for an object property (good for array object properties or just to JSON a single property) and I'll be working on others to encode entire components, etc..
No, I had no plans to release it. I don't have time, or even the desire, to provide support so if I released it there's a bit of obligation to do so. It also uses a custom converter I wrote so that'd need to be released too.
There's also a current bug with it handling Texture2D properties that I'm working on resolving (it should encode it to name property, but fails).
I also plan to extend this to handle arrays of data, because I hate having to use a proxy for array maker. If I encode/decode on the fly it should be pretty reasonable to have arrays of data. Obviously I can't encode everything, but it should work for most cases (like inventory data, etc..).