My Mother is an ENTJ and my stepfather is an ENFJ. He's definitely the warmth in our home while she's the structure. They help balance each other out I think. He somewhat softens he personality and discourages her from living in her office. She keeps him from following his enthusiasm into ridiculously over the top projects.
I've heard it said that it's like two generals trying to occupy the same space, which is not exactly true to my experience. Lots of similarities, but just enough differences around crucial points that it can be enervating. The chemistry can be white hot, though. Both types tend to have big personalities, and we feed off of each other. You feel you could rule the world with them by your side. Everything is over the top, grandiose, fabulous, and a little gaudy. The heights are sublime, and the lows are blow outs. Pure fireworks all the way around.