These are my particular thoughts and feelings towards ESTJs, being an INFJ myself.
I don't know, maybe it will be helpful for some.
Though I have probably met many ESTJs in my life, there are only three that I have had meaningful contact for the purposes of this thread. Two of which are older females (a professor and my aunt), and one who is my friend (male). Though I am not usually vague when it comes to discussing other people, I will try to keep my observations as literal and objective as possible so as to avoid any misinterpretations.
There are very noticeable differences between the ESTJs I know, though my prof. and aunt are very similar compared to my friend. The first two fall would fall under the logical subtype, while the other under the sensory subtype (this based on Gulenko from the socionics.org site). Like I said before, there are difference between them.
From what I have read from people's observations, the administrative subtype seems to be the stereotypical ESTJ. A probable reason for this is the fact that they, in some way or another, will have there presence felt wherever they are. Also, they have no reservations in extraverting their qualities, making them easy to recognize. The two I know are very hyperactive, being able to sleep less hours than the usual person but still having a large amount of energy to undertake all of their many daily tasks. They specially take pride in this fact.
Also, you will seldom see them resting while they are in the outside world. There is always something to be done at any time, even if what they do might be considered unnecessary to others. Though it may appear otherwise, they actually enjoy having a thousand things to do. I say "otherwise" because they tend to look overagitated and often mention everything they have to do as if they were complaining about it.
It might be a coincidence, but the female logical subtype seems to be more service oriented, as in wanting to take care of people in the way that is 'supposed to be.' Since I am not too knowledgeable in socionics, I will only suspect that this is due to . For instance, if you are feeling sick, they will follow a predetermined procedure to help: tell you to sleep well, "for that condition drink this," etc. I find their concern very touching, since they will not stop until they help you, or until they consider that you do not need their help anymore. However, they do tend to exaggerate this quality at times, as if to avoid others questioning their affection level.
Since I started to mention , there is another aspect of ESTJs that I consider to be realted to it: social hierarchy. There are other types who have an appeal to this I believe (not sure if SJs in general have it). In any case, your name and stature is important to ESTJs, because they need to treat you accordingly. Depending on your occupation, you will receive the respect you deserve. However, they will probably get upset once they see that you are not what is expected from your position.
The ESTJ sensory subtype could not be any different. The biggest difference I can perceive is that they are more subdued in terms of hyperactiveness and they are not especially inclined to administrate/lead. Also, they are considerably more introverted. Typing my friend was difficult because he did not fit into most of the estj descriptions I read, which made me think he was an introvert instead. Actually, when ESTJs hang around me for some time they seem very relaxed for some reason. I haven't figured out why this happens yet. In any case, my friend is definitely different from the logical subtype. They seem to enjoy following more than leading. Not that they don't like it, it is just that they know the requirements of a leader, and they seem to lack the large amount of energy characteristic of the other. I might go as far to generalize that the sensory subtype has a fuller figure compared to the logical subtype.
From what I have observed, they seem to be more aware of their hidden agenda of . They enjoy talking about societal issues, and how things have come to be. Also, they are slightly more social and emotional, and display more warmth than the logical subtype.
In terms of duality:
The problem that I see with INFJs and ESTJs at first is that INFJjs will be turned off by the ESTJs' seeming insensitivity, while the former will not notice INFJs in their busy lives because they are very introverted and secluded. This will happen particularly to the more introverted INFJ and the more logical ESTJ. However, I believe that the two represent a perfect duality, in terms of the contribution to each other. The more logical ESTJ with the more intuitive INFJ is probably the basis for the description given in the duality relation between both types. Definitely the objective of the first will be to take care of everything around the house (literally) while the second, besides calming, takes care of the future planning. Or course there is much more to it than that, I am only giving very brief examples of the duality.
Being more of a logical INFJ, I can see how a sensory ESTJ could provide more of a complement in my case. To tell you the truth I don't like to write statements like that, since relationships between different types will provide unique contributions. I am simply stating that, based on its description, there is more duality. For one, I will admit that I am dominant at times, wanting things to be done the way I want. It sounds terrible, I know... Let me put it in a nicer way: I feel that I know what has to be done. This, combined with an over-the-top , makes me seem bossy to others, which I pick up easily at times. In summary, I am more dispassionate to others, which suits me well for the sensorial ESTJ. My friend is more friendly than me and is not so insensitive as what is regarded 'ESTJ behavior.' Also, he is more laid back when it comes to tasks, preferring not to have so many things to do. However, they are definitely not lazy. One thing I like is my friend helps me not to feel so much like a cold person.
What I have found might be a reason of the comfort level between INFJs and ESTJs is that both don't expect basically anything from each other. Personally, everything that my friend does makes sense. Though, in general, ESTJs have a tendency to not think of the overall reason for doing tasks in the first place, making them sometimes do things that I feel are unnecessary.
I will leave it like this for now, adding more throughout the thread when necessary. Yes, this is not something I usually do (leaving an openended post). Please, try to keep this thread clean by not adding unnecessary posts. Let's try to post things that might add to it, rather than just comments. If I made a mistake somewhere, please let me know.