I have a free standing stove the sits out from the fireplace and with the upward heat it generates there is no way I would put anything above it.
I've a tall marble fireplace with the mantelpiece about 2 foot above the stove and you wouldn't put your hand on it when the stove is in full swing.
Incidentally, my sister has the insert stove in a similar sized room and she says and I agree there is no comparison between how hot mine gets the room and hers.
Stands to reason, all sides of the stove are exposed to the air as opposed to just the front on the inserts, the rest being in the wall..