Lux is pretty good, although certainly not great. It's admittedly plagued by a lot of issues common to this era: bad expositional dialogue, a rather rushed third act, etc. Still, I really quite liked the concept here. Cumming is great, Mr. Ring-a-Ding looked great, and I quite liked the animated segments. Of course, that brings me to the elephant in the room: the fourth-wall breaking and the actual fans. On one hand, I found most of the dialogue to be pretty poor, and it felt almost question-begging in its assertions about the fandom. On the other, it was kinda sweet in an odd way, and seeing the Doctor physically come out of a tv was fun. Overall, this wasn't anything super amazing as an episode, but it's certainly a big step up from The Robot Revolution.