They have been tested and subjected to much more than 99% of people will ever subject them too. A guy I know went to the testing at the Ford proving grounds and drove all the new trucks and said they are all impressive especially the Ecoboost.
After the mess Ford had by introducing the 6.0 too soon to market they will NOT let that happen again. That is also why the new SD truck has the strongest transmission available of any 3/4 or 1 ton truck.