It's fine. The pacing is a little slow but there are plenty of good moments and I enjoy Suzan finally getting her time to shine. The slow pace helped with the build-up of mystery in the first episode and didn't detract too much from the political plots, though it might have if I wasn't using this opportunity to make progress on my current crochet project.

There are some parts of the story that fall apart under scrutiny (such as the Sensorites being unable to recognise each other without their roles being communicated) but most of the plot is fairly solid, something that often feels like a rarity in Doctor Who.