The location is absolutely wonderful, in a quiet garden street very close to Belsize Park Tube and to Primrose Hill and Hampstead Heath. For breakfast, the cafés on England's Lane are around the corner, and Gail's on Haverstock Hill is five minutes' walk. The bedroom itself was clean and comfortable and full of sunlight first thing in the morning (which I like, but note there are no blackout curtains). It was very quiet as it backed onto a garden. The shared bathroom was large, with a good shower, and I particularly appreciated the shampoo and conditioner Max provided.
A few caveats: there was quite a bit of mildew in the bathtub and shower. (There was also no trash can in the bathroom, not ideal for female guests.) There were regularly dishes left unwashed on the kitchen counter overnight, and I came back one night to find a mouse in the kitchen, which Max assured me was a rare occurrence. That said, if you're relaxed about shared space, this is a great option.