As a gunner I dont like the nose down method. If you think or you can out-gun the other hogs gunner, because as RJ said it sends the hogs into wheelies and the gunner loses his angle of the other gunner or groundpounders shooting at him. Then if it makes the whole hog one-shot a groundpounder can put a few br fire into the hog then you die...
But the nose down method is very affective agianst ghost,mongooses, low flying banshies or hornets and if your lucky choppers that are not paying attention.