"The First Days of Christianity" is, on the whole, not worth the money. The only possible exception would be free copies.
The first part covers the "Holy Family". It uses the Gnostic Gospels as a reliable source despite the nearly universal rejection of them by modern reputable scholership. As a result, the first portion of this poorly executed attempt at an entertaining biography is largely innaccurate and biased. The reenactments of loosely related miracle accounts are worthy of a high school play at best. If you do choose to buy this, don't even bother with the first section.
The second part is a head and shoulders improvement over the first, but it still falls far short of a well done documentary. It clearly favors an atheist (or at the very least agnostic) viewpoint in reporting the history of the very early church. As the timeline becomes more removed from Jesus and the history becomes less controversial, the documentary improves considerably.