For me at least. Episodes 10 & 11 really brought down this story for me. I feel like Never Let Me Go started out so strong but somewhere along the way it lost its way. It's like the writers lost interest and were just trying to finish it the soonest possible. It was pretty obvious because things started to make no sense. Character motivations sometimes felt out of nowhere and left people scratching their heads with their actions. Some characters were just a waste of space eg Ben and Chopper. Seriously, what was their point in this series? The villain was also laughable. The writers intent was to make him this scary, unstoppable force but in the end he just came out as a clown.
Also, something happened with Phuwin and Ponds acting after episode 9. It was very flat and like neither of the two cared how bad their performance was. They just wanted to be done with it and that's that. That's one of the things that took me out of the series and made me lower the rating to 8.5 paired with the plot holes. Aside from that I feel like before they hit episode 10, they were really giving it their all and I was enjoying watching them portray more mature roles compared to their time in Fish Upon the Sky. The story and acting may have been up and down but something that wasn't was their chemistry. That's really what kept me coming back episode to episode. Luckily episode 12 felt like the beginning of the series again both in the acting department and the writing. I was satisfied with the way it ended.
Despite my huge problems with Never Let Me Go towards the end. I still pretty much enjoyed it and thanks to episodes 1-9 & 12 it's one of my favorites of the year. Due to the suspense, acting, chemistry and action aspects of the series. The filming locations were gorgeous. If we ever get another series like this, I hope the writers sit down and watch some of the mistakes they made with NVLMG and improve on them. Overall I give this an 8.5 and would recommend. Despite it's flaws it's still worth a watch.