SEAL Team Six vs. Delta Force: Running and Gunning

When SEAL Team Six operators run with a rifle, they're often running "muzzle up." In contrast, Delta operators usually run "muzzle down." Which is better? In the next two videos, Kyle Defoor (SEAL Team Six) and Paul Howe (Delta Force) discuss their views:
I've used both techniques, and environmental awareness is critical: don't aim at anything you don't wish to destroy/kill. If I'm loading onto a boat, I don't want to put a hole in the deck. Likewise, if I'm loading onto a helo, I don't want to put a hole in a main rotor blade. Both muzzle up and muzzle down can be used to run fast as is seen with Defoor's example above and Pat McNamara's (Delta) example below:
SEALs have been using "muzzle up" since Vietnam:
Even so, Vietnam SEALs also used muzzle down. Another important factor to consider is training: follow the rules of the instructor/range. If the instructor is a SEAL, muzzle up will probably be allowed more, but if the instructor is a Delta operator, he'll probably expect much of your movement to be with the muzzle down. When in Rome, don't piss off your instructor. In summary, situational awareness and safety are key in deciding whether to go muzzle up or muzzle down.
P.S. Dalton Fury (Delta) was kind enough to add Kyle Lamb's (Delta) remarks to the discussion, so I posted the video here while I try to figure out how to enable links in the Comments: