From people I know, there are a lot of similarities between the two types, but the "N" sees things on a larger (global) scale.
The ENTJ's I know (I've met and identified a few recently) have these grand schemes (they are large and sometimes complex) that they are involved with. As examples, I know one who is growing his business very well. He wants to reach outside of his own city, outside of his own state in order to expand. Another one travels a lot and meets people that will expand his network and his own skills.
The ESTJ's I know are very similar but on smaller scales. I'm not saying that N's are better than S's, just different. S's seem content, generally speaking, to have their job/small business right there in their hometown and surrounding area. Sure, they may like to travel to other places occasionally, but it's not necessary.
ENTJ = the world is my oyster
ESTJ = this city is my oyster
I asked an ESTJ once (2 of them, now that I think about it) who is extremely good at what he does for a living (they both were actually) - but I basically suggested to them that they expand their business. I could see them having a lot of success if they expanded and had multiple jobs going at once/multiple clients and they both seemed puzzled and/or offered explanations of why it wouldn't work or why it wasn't practical to expand (i.e., if you expand, you lose control because you can't be in 2 places at once, there's risk, it's harder than people realize). The answers were very similar by these two individuals. They wanted control. They wanted to be right there where the action is and they wanted to be in control. They got results that way, so I don't blame them. But, when the idea of expansion or "getting bigger" is suggested, it's not something they want to discuss for very long. They're content to keep things small (compared to the ENTJ) and very managable.
The ENTJ, I think, is seeking expansion - ways to get bigger.
Another example of bigger picture/smaller picture is that I see ENTJ's being anal about big picture stuff. They don't like the way so-and-so conducts business, they not happy that they lost one of their many streams of income, they don't like the way their website represents their business, etc. I see ESTJ's being anal about smaller scale things - you didn't use that tool properly, you didn't fold your sleeping bag the right way, why is there a McDonald's bag in the trash can - I thought you were on a diet, my leftovers in the refrigerator are in a different spot - did you move them or eat some of them?" The kind of stuff that would drive an N up a wall in about 4 seconds.
No, I didn't eat or move your food. Number 1, cuz it's not my food and that would be rude. Number 2, cuz I know you're an ESTJ and you notice everything. Nothing gets by you, so I'm not going to give you anything to gripe about (even though you'll still gripe about something). Yes, I had McDonald's cuz I felt like it. In fact, it was so good I think I'm going to go back right now and eat it again - twice as much this time. Wanna come along?! My treat! You worry about you and I'll worry about me. These antics work with ESFJ's and ISFJ's, but most N's don't have the patience to talk about these kinds things. Why is it so important to pick apart every little thing. It's brutal to listen to. Makes one want to pull one's hair out.
/rant