Barfs on large files, needs language support for popular web languages.

I use Cocoa JSON Editor just about every day, so I gotta say its good. But I often get large JSON data structures, like RDF graphs, and it just cant handle it.
I like that it shows me the equivalent Objective C data types, but I wish it worked with other languages, especially Java.

But in terms of pointing the way to usability and good WYSIWYG, this app has no competition. Its cool.

newWaveHippo about Cocoa JSON Editor