I have just finished watching the whole 6 episodes. Very good right up until the very end, where (in my opinion) it fell flat on it's face.
6 of the 6 and a half hour event was very good, last 30 minutes let it down.
Others may disagree but that's my ha'pence worth.
It would be easy to pick it apart if you look too closely but it is definitely a class above the normal dross being dished out these days. I would recommend watching it, but be prepared to be disappointed by the very ending.
I won't give any spoilers other than the disappointing (IMHO) less than expected ending.