I really love this episode, and did from the first time I watched it in 2014. It's an immediately engaging episode, and Peter Capaldi gives a powerhouse performance as the Doctor cycles through several different emotions. Jenna Coleman matches him beat for beat the whole way, exemplified in the diner scene where the two snipe at each other. The return of the clockwork droids was a fantastic idea, and the Doctor's serious conversation with the Half-Face Man is a highlight of Capaldi's entire era. Finally, the end where the Doctor tells Clara 'you see me, but you don't see me' is heartbreaking. Don't know why people cite this episode as starting the era off on the wrong foot, I think it's a thrilling intro.