During our Stanford hackathon in Oct 2011, I had recommended that using JSONP is a good idea. But as more and more time goes, I see that since all our calls are authenticated, there is no reason for not doing CORS. Infact, in production we will be doing all REST calls over https. This means our domain/server will be verified to be only us and avoids the man-in-the-middle that is a possibility with CORS, when using Access-Control-Allow-Origin: *