ive felled all sorts of trees in all sorts of situations. at the top or the base, gravity is the same. what ive seen is that if the tree happens to come back on you and it hollow, that angle created by the angled cut acts like a teeter and can flip the butt end into the air maybe even to the side vreating a potential hazard. as eric said the conventional and the humbolt done correctly will prevent kickback. another problem is that if for some crazy reasonthe feller needs to swing the cut {remove one half of hinge to cause it to tip to other side} they are unable to do so. if your using the angle cut to prevent kickback your going about felling all wrong. if your in the tree , cut higher and shorter to prevent the piece from lodging into another tree. dont rely on that angled piece thats withe the grain to prevent the top you cut from blasting back at you. on the ground an properly executed conventional will allow you the appropriate time to remove yourself from the danger area. if your still worried about kick back take the 5 min and tie off thebutt to the stump. i dont agree with the angle cut idea.
