hstore is all kinds of awesome, but one limitation is that the values are pure text. You can nest an hstore inside another, but only if you're smart enough to know that it SHOULD be treated as an hstore; as far as Postgres is concerned, it's text that happens to contain '=>'.
If JSON support means first-class type support in a nested object, that's a huge leap forward.
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Look at PostgreSQL's hstore data type - that's pretty much what you're asking for.
hstore is all kinds of awesome, but one limitation is that the values are pure text. You can nest an hstore inside another, but only if you're smart enough to know that it SHOULD be treated as an hstore; as far as Postgres is concerned, it's text that happens to contain '=>'.
If JSON support means first-class type support in a nested object, that's a huge leap forward.