On short: clean place, EVERYTHING you need in a flat (better than a hotel, there was nothing I could not find in the apartment when I needed it), good bed, fluffy towels :), good shower (there was a comment on the shower from one of the reviewers some months ago, the heater was probably changed as we did not have any issue with the hot water), and good value for your money.
The host is extremely responsive, always answering to messages in a few minutes; easy to talk to and very clear in his replies.
We spent 8 nights in his flat, so enough time to appreciate the accommodation and the area. It's close to the underground but if you feel you want to walk to some of the major sights, you can do so. There's a cafe in front of the flat, and a local food store literally across the street. There was no noticeable street noise, it's a quiet flat.
So, on the plus side: hotel-like room, everything you need is there, good sleep, and a very helpful host. On the minus side (nothing is perfect!), the room is at ground level but lower than usual, so a bit difficult to keep the windows open for a long time as people walk directly in front of it. Of course, you would anyway keep them closed in the summer, as you can use the AC in the room.