1. Price -- the price is the $500 lower than I've found anywhere else on the internet, no sales tax and free 2-day shipping.
2. Packing -- extremely well packed! Frame tubes were wrapped, then entire frame was zip-tied to a large sheet of cardboard before putting it all into a bike box. Best technique I've seen!
3. BMC build quality -- It seems that the state-of-the-art in carbon frame building allows manufacturers to crank out carbon frames in volume with excellent structural integrity. However, don't expect the cosmetic finish of a 1970's Colnago or Schwinn Paramount. The BMC clear coat is shiny but uneven; looks like shrink wrap unevenly applied. Not a defect, but definitely not like a first-class old fashioned paint job! My other road ride is a 2011 S-Works Roubaix -- the finish is no better (just different). Funny, but the carbon weave finish on 1990's Kestrels was better!
4. Ultegra Di2 -- I have Dura Ace Di2 on the Roubaix and, to the casual eye, there's only a cosmetic difference between the two groups -- I'd be hard-pressed to pay the extra $$$ for Dura Ace again!
5. Easton stem and carbon EA SLX bar appear comparable quality to Specialized S-Works. Easton wheelset is about 100 grams heavier than DuraAce carbon and hubs look cheap; have to see how they perform. For training they should be fine. Easton freehub definitely not as smooth as Shimano.
5. Out of the box the bike weighs 15 lbs 7 oz without pedals (50cm size).
All-in-all I'm happy with the price, shipping and initial inspection -- at $4499 it's a good buy (at $6999, not so much).
Snow and sand/salt on the roads have kept me from doing a test ride yet; maybe this weekend.