What a terribly strange and baffling idea this was.  I'm not against the idea of Space Babies, I suppose.  I mean it is a tacky idea straight out of the 90s but any idea can be fun if executed well.  It looked just awful though and their whole side of the story was quite boring.  I don't hate the way we speed ran through Ruby's introduction to TARDIS life, but it does feel silly and makes the episode a poor introduction to Doctor Who when it really, truly shouldn't be one.  This is the big start to the new Disney partnership with Doctor Who (previous year specials aside) and it's a truly awful experience.

One thing working for Space Babies is the stuff around Ruby's mysterious origins.  In hindsight, this mystery has no pay-off down the road, and while that's not entirely on this episode, it does make that stuff feel pointless, because while those scenes are cool here, they aren't paid off in any way in this or any other episode.  So no, it's not very good.  It might be one of the worst, if not the worst, series premiere in all of Doctor Who.  And it's a real shame because I quite like the rest of this season.  It's pretty fun, but this was a bit of a train wreck.