I agree with RobertSunrus
I purchased a 2010 6.4 at the beginning of this year. I struggled with the decision mainly because of all the horror stories the 6.0 left. I did a lot of internet research and determined that after the Gen 1 the 6.4 was fairly bulletproof - as long as you did not mod it.
MPG? It sucks - but I did not purchase it to save a few bucks during a fill-up. I purchased the vehicle because it was half the price of a new 6.7 (an awesome vehicle) and the power and response of the twin turbo's.
I added on the 7 year/100,000 mile Ford warranty, and for a few grand put to bed all of my what if worries.
Keep it lubed, perform all of the scheduled maintenance, and put in all of the additives recommended by Ford and the 250 should last for years.
"Suck it up, spend the bucks, do it right the first time."
WBCCI # 1113
Trailer '78 31' Sovereign
Living Large at an Airstream Park on the Largest Lake Totally Contained in Texas
Texas Airstream Harbor, Inc.