OK, here's my feelings about it, with NO spoilers!
1) I loved the pacing!
2) I loved the way in which the characters were brought into the story.
3) Wow, THAT was Diana Rigg? Awesome. granted, I will always remember her as this:
...but still cool to see she has fire at this point in her career. :)
4) Jenny, Strax, Vastra. Especially JENNY! Finally, not the sidekick!
5) The story was good; the acting pretty good, for the most part. The daughter was 'meh' until the end, but I thought redeemed herself nicely.
6) I enjoyed it, though a lot of people are saying they didn't. I think it is because of how the story progressed and was presented (which I liked, as it broke from the norm) and not so much what the story was.
7) The very end of the episode annoyed me. When you see it, I think you'll agree (and also why the preview of next episode kind of annoys me too.
I think I covered all the bases without giving anything away that hasn't been shown int he preview clips from the past week.