I stayed at Luisa's flat for a month, and I had a great experience.
wifi speed: Good. 25 Mbps down, 10up? I was working remotely and had regular video conferences with coworkers, and they all confirmed my video and audio was clear. Occasionally the video on my end would get choppy with numerous people on the calls, but the audio was always clear.
The flat was clean and beautiful, with everything I needed. If you're missing anything, just ask Luisa. She was always ready to help, and help me find things I needed.
The location is perfect, and I loved being close to so many great restaurants, and a quick walk to the bus or tube.
Definitely recommend this spot!