I put about 40 miles on mine today (picked it up at Noon) and it is averaging about 21 MPG on mixed driving. I got on it a couple of times and drove into town a couple times (about 8 mile trip one way). So I would say it was mostly highway miles. I was up to about 22.5 before I got on it the last time....
I did try to vary the speed I was driving and I had the air on...
I did insist that the dealer filled the car up with premium and they did... So far so good....