USMC attack pilots are trained specifically to support Marines on the ground in the close fight of amphibious operations. AH-64s, OTOH, are designed primarily as a tank killer, and units train primarily for this mission as the ground commander's attack force against enemy massed armor in the attack, defense or counter-attack mode.
**Note: Although the AH-64A and D models share the same powerplant, transmission and are similar in appearance, the D model is completely different in terms of detection (radar), survivability(fire and forget missiles) and communications (digital).
It comes down to the focus and intent of pilot training.
We [The Corps] puts our pilots through infantry school first in order to lay the foundation that they're sole purpose is what is taking place groundwise.
They learn how to orientate themselves toward terrain and enemy from an infantrymen's perspective.
So as a former Marine on the ground in an offensive or defensive combat scenario...given my choice...100 times out of 100 I select the Marine Corps piloted Cobras.
But...if I were riding on top of a transport and a grip of T-80's came rumbling over the horizon...I'd rather have the Army piloted Apaches.
Given the circumstances in Anaconda...I would have rather had the Cobras.