I stayed here with a friend in late July. We had a wonderful week in London and the flat certainly contributed to that. The location is fantastic, near Goodge Street and Tottenham Court Road stations, with restaurants, shops, and a Tesco a very short walk away. (We particularly liked The Fitzroy Tavern.)
My friend took the bed, and I the sofa-bed. The latter may not have been the most comfortable thing I've ever slept on, but I didn't wake up with odd pains in my back or get poked by loose coils as has happened to me in the past. There is a smart TV which we used a couple of evenings. Also, the shower had unexpectedly good water pressure.
I would say our only mildly significant issue was that, due to the hot weather in conjunction with somewhat inadequate ventilation, the flat was at times warmer or more humid than the outside. Therefore, the bathroom towels never seemed to dry and our laundry took two days to do so. If you're not traveling in summer, I doubt you would even notice this.