First is Space X which likes to violate every rule in the book. From planning to board the astronauts before they load the propellants, to using ultra cold LOX that makes for a tricky fueling cycle, to finally having it come out that the ultra cold LOX was causing the engine turbine to crack when operated. And none of this includes the fact the Dragon 2 capsule for manned flight intends to use RATO engines for landing.
While SpaceX has these issues, Boeing just has one: man rating its Russian engine for the Atlas V. In truth its real problem is actually making an engine for the Atlas V so we can cut the cord with Russia on Space launch period. The use of the Russian engine has always been a liability and in this time of Ukraine and Syria, we should have had an alternative years ago. No, instead of spending the time to man rate the Delta IV heavy, and potentially allow the use of Orion for low earth orbit, we choose to stick our face in the sand and let ULA continue to offer an engine/vehicle that we can't man rate under any circumstances. Regardless of what their arguments- ULA or SpaceX- someone needs to step forward and give some real answers. For if things between Russia and the United States get any testier, the inability to do manned launches could be viewed as deliberate sabotage.