What do you like about JSON Feed?

One of the downsides I saw when evaluating JSON Feed was that it doesn't use GUIDs, which can cause problems when the same post is present in multiple feeds (I.E. syndication).

When I last looked I found that every feed reader supporting JSON feeds also supported RSS/Atom and every website with a JSON feed also had an RSS or Atom feed, so it seems easiest to ignore the JSON Feed format.