[Im a lot more explosive than I look SPOILER] I saw some negative press for this one, but I quite enjoyed it. The whole hologram father thing put me in mind of the data ghosts from David Tennant and Catherine Tates' "Silence in the Library", but much more sophisticated, almost like Black Mirror's "Be Right Back".
I was unsure about the whole resolution until the Doctor explained it, and it made some sense, so not a cop out like it appeared to be for a second.
The biggest thing for me was when the computer started getting stuck over Ruby's next of kin. It could have just referred to all her family being long dead, but I'm hoping it meant something more than that. Hoping they're not going for the "she's her own mother" twist idea, but rather hoping that maybe one of the characters introduced in the episode may turn out to be Ruby's mother. Maybe it will turn out the computer is some sort of automated version of the mother - we didn't have it explained who the old lady was in the picture.
The single snowflake at the end might mean something - maybe the little girl will turn out to be Ruby's mother?
I love how Ruby seems to be getting better in this episode; some of her lines put me in mind of Rose and Clara at their best.