Absolutely fantastic. The scariest Who has been in some time, I nearly wet myself when the figure under the blanket stepped behind Clara.
Some will say its derivative but like the very best of composers, Moffat is capable of taking riffs and licks he's used before, and still forge them into something that is both new, and brilliant.
That is talent!
Loved the awkwardness on show from Jenna and Anderson (Danny Pink is seriously great) loved the creepiness of the orphanage and the spaceship at the end of time, and as for the twist in the barn...well some will (and clearly already are) complain, but then they're the same ones who probably didn't bat an eyelid when RTD implied the Master had always had drumming in his head. The show is always at its best when it takes risks, and I have to say I don't quite know what the big huge problem is, from the screeching some drama queens were doing after seeing the draft version I thought Moffat was going to suggest Clara was the Doctor's mum or something
Jenna is seriously wonderful this series, from a character I could never fully warm too I think she's fantastic now, and though I hate to say it, she works better with Capaldi than she did with Smith.
Finally this brings me to Capaldi, probably the first episode where I've really felt like he was The Doctor, long may this continue.
When Moffat's good, Moffat is great.