This sweeping series starts with the creation of the tank as an powerful innovation which helped to overcome the grinding deadlock of WW1 and follows tank use and design through to modern day questions about whether tanks may be obsolete. I am not a 'tank expert', and from my point of view this documentary contained some new and fascinating insights that I had not come across before, often via interesting interviews. In particular, Russian and French experiences with tank development and tank tactics stand out. However, the series also inexplicably leaves a huge amount of widely available and important information out. The almost complete absence of commentary on US and Commonwealth tanks from WW2 was particularly conspicuous (apart from a short part on the US Sherman tank). It's commentary on the geopolitical contexts of the events being described also sometimes seemed to be lop-sided at times.
If you want a different perspective on tanks and tank warfare, you may enjoy this series. However, be aware that it skims over or completely omits significant events and details, and conveys a number of interpretations and opinions as though they were facts.