I've watched the first two and enjoyed them so far.
It's a good story, bu I do have some gripes though...
First, it's very much overdramatized, which is par for the course for the History Channel. Take for instance the gun battle where the Pinkertons were brought in to crush the strike at Carnegie Steel. They made it look like a fucking Civil War battle - guys getting shot in the chest all over the place, and then the voice over says eight people died.
I also take exception with the general thesis and title... The Men Who Built America... They really haven't talked about much that these great men actually built. Vanderbilt presumably had a hand in building the country's railroads, but they gloss over that and talk more about the stock he bought and sold. Carnegie oversaw the building of a bridge and was the benefactor for the music hall that bears his name, but those are about the only things they've talked about being built in this miniseries. The protagonists have destroyed or shut down more things than they've built in this story so far... bridges, railroads, factories, dams, entire towns, each other...
Also, I could do without the cut-ins with opinions from guys like Donald Trump, Mark Cuban, Donny Deutsch, Jim Cramer, etc. The story is good enough without them and I don't need to hear them flatter themselves by trying to relate what they've done to the likes of Vanderbilt, Rockefeller, Carnegie, etc.