Mine is still under case received. Just called USCIS on 12/8 and asked them to expedite the case. They asked if my case falls under any of the expedite reason and I said that I have a job and if I don't join company may have financial loss. They asked me on which documents I can submit and I said offer letter and HR letter they said OK and give me a reference number for expedite process.
This happened on 12/8 and under case history from myUSCIS-Case status showed following
On December 12, 2014, your request to have your case expedited, referral number XXX, was completed.
On December 12, 2014, we sent a response to your request to have your case expedited, referral number XXX.
On December 10, 2014, your request to have your case expedited, referral number XXX, was assigned to an officer for response
We called again on 12/12 Friday to check on expedite process and they asked to wait until i get the letter from USCIS about the decision. This is so frustrating.