At the time that this article is being written, the episode has a rating of 6.4 on IMDb, the lowest of any Doctor Who episode since 2006's "Fear Her" (6.2). It also has the dubious distinction of being the second-lowest rated episode since the show's revival in 2005 (behind only "Fear Her").
However, Steven Moffat has a different take on the episode. When asked at the recent premiere of the 2014 Christmas special, "Last Christmas", which series 8 episode was his favourite, he said:
"I think I’d give a shout out to an episode that I think will grow in stature over the years because it’s so beautifully and elegantly written, In the Forest of the Night.Do you think he's right? What did you think of "In the Forest of the Night" when it aired, and has your opinion changed upon rewatching it? Tell us in the comments!
There were people who thought it was maybe scientifically inaccurate – they’re wrong, I checked with the scientists – and any piece of television that includes the line of dialogue ‘catastrophe is the metabolism of the universe’ as a part of popular entertainment has to be… a beautiful episode!"
[Source: Radio Times]