I personally found the documentary to be very entertaining and interesting, but I wanted to see what the experts here at /r/askhistorians thought of it.
There is a /r/badhistory thread that you may be interested in about the show, link here. To summarize, it's pretty Eurocentric, and not very good at fact checking. It also makes lots of grand, sweeping statements that really don't stand up to scrutiny. In short, don't trust anything you learned from it.
It is a TV show meant to entertain. Nothing more, nothing less.
Even as far as TV documentaries go, though, I found this one particularly shallow and sloppy.