I really liked this episode. While I thought Clara going a bit insane in the beginning was a little OOC, the mausoleum bit was very interesting and the twist with Missy, while people were already predicting it, I enjoyed because it because it's refreshing to have a full on Time-Lord as The Doctor's adversary again. Missy's character is also a lot of fun, eccentric, manipulative, and a brilliant psychopath.(That bit with Chang was a great at showing what she can do.)
Danny, while boring in most episodes, has a nice little scene where he confronts a kid that he killed because he didn't look into the house properly. A little poetic seeing as he himself was killed because he wasn't paying attention.
While everyone saw the Cybermen coming, I enjoyed how they they're using the minds of the dead, trying to get them to willingly delete their emotions, rather than going after the living through force again. I'm not sure if they've done this kind of thing before but its nice to see these guys back as well. Actually, now that I think about it, the only part that I don't like about them are their voices. So them being silent this whole time is a nice bonus.
All in all, great part 1 with a great setup and hopefully a better payoff next week.