I am bewildered by the poor reviews. I lived through this period and I found the story, the dialogue and the acting exciting and convincing. The characters are very varied and the twists and turns gripping and unforeseeable.
If one is looking for mindless action as per James Bond or the others, this is not for you (not to say there is no action: there is, but it is properly integrated into an interesting story). If you are an intelligent viewer who likes to be challenged a bit, go for it.