Don't forget AF447 (recent A330 crash)
Let's not forget the rather recent Air France Fl 447 crash in the Atlantic Ocean... many unanswered questions related to instrumentation (pitots), air data computers, too much automation, possible pilot error (flying into known CB), or combination of contributing factors that negatively affected the flight that dark, stormy night.
The unknown contributing factors should certainly be considered with respect to the tanker competition (as they relate to the airframe anyway). At the very least, delay the decision until the final report is published.
Too bad that the Pentagon and AF acquisition officers won't even consider a short-term alternative...
DC-10 conversion to KC-10 utilizing mothballed and/or retired DC-10 aircraft. Heckuva lot cheaper than buying new, and the AF has experience with the KC-10 already. Probably pick up 180 or more fully retrofitted (and refitted with latest avionics, engines, etc.,) for less than $30 million each for a total of $5.4 billion.