High quality and well done but by the end of the first two series it’s already shown you all it’s tricks and it’d probably have been more highly regarded if it had ended there. As it is things feel like they are going in circles by the third series with some of the extreme actions not only losing their shock value but also their credibility through over use. The final series is the outlier shot without Spacey where the plot descends into an unbelievable farce with a underwhelming and rushed finale that felt like the plug was pulled early at short notice and this was the best they could do.
Conclusion - The first series is excellent and well worth watching, the second starts to lose the drive but is still very good, third, fourth and fifth feel like more of the same to cash in and watching the sixth will only lower your opinion of the whole. It certainly knocked a star off this review!