The two sources of power handle<em>very</em>differently. His internal power source is very easy to draw upon, shape, and use, but the very act of drawing upon it drains him. The Queen's power, on the other hand, is very difficult to tap into, and almost seems to be fighting against him, but the only drain is the struggle with it; the power comes from elsewhere, so it's not sapping him. The good news is, between the two, it gives him a great deal of longevity; his internal power is quicker to use, but comes at a cost to him, and the Queen's is nearly limitless... as long as he can successfully draw it.