Bret Chase
Minister of Fire
Have never burned oak, and only burn hickory from time to time (I find it burns hot but fast), but I can vouch that sugar maple, although ti has beautiful green flames, cannot put out the heat that Ironwood does. It is still a good heating wood though. Keeping my home nice and warm.
Oak < Hickory as far as heat goes.... but I like a shagbark's shade so I seldom cut them down... well that and there's probably 10 oaks to 1 hickory in my area...