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
Case History
12/12/2014
On December 12, 2014, your request to have your case expedited, referral number XXX, was completed.
12/12/2014
On December 12, 2014, we sent a response to your request to have your case expedited, referral number XXX.
12/10/2014
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.