The pros: The location is wonderful, with lots of nearby cafes and restaurants, and just a 10 minute walk from Oxford Circus. Self check-in was straightforward, the flat was clean, it looks as it does in the photos. Considering it's near busy roads, the place itself is quiet and we were able to get restful sleep.
Unfortunately, there were some extenuating circumstances that made our stay difficult, but Denny managed to message us to explain afterwards, and we understand that things were out of his control. The Internet was not working due to a mix-up with a new neighbor, which was unfortunate, since we were in London for a family emergency and intended to work in the evenings. Hopefully it gets resolved very soon for future guests.
I would still recommend Denny's flat. It was really just a case of Murphy's Law for us, I think :)