I don't own the DVD, but I'm watching the show on the History Channel as I write this. It certainly has its share of interesting tidbits, especially when discussing Roman engineering and architecture. Unfortunately, it clearly values sensationalism over accuracy in retelling the history - for example, it states that Nero was the prime suspect for starting the Great Fire of Rome, retelling the story about him playing the lyre ("fiddling") while Rome burned. However, the most reliable Roman historian, Tacitus, who was alive during the fire and who generally was anti-Nero, informs us that Nero wasn't even in Rome when the Great Fire started (and even praises his reactions to the fire); as this wouldn't fit in with the overly simplistic portrait the show paints of Nero, though, it is not mentioned. When a show makes mistakes such as these, common knowledge among Roman historians and easily researched, it is difficult to trust any of the history it relates. Most of the commentary by experts is fairly basic, with little that is particularly insightful or thought-provoking.
To sum up, the program is fairly strong when covering the specific engineering feats, but unreliable whenever it moves to Roman history and culture.