Myself and a friend stayed at Naza's place when both visiting Madrid for the first time. It's a great location, with plenty of cool bars and restaurants in the neighbourhood. You're a 15 minute walk (uphill) to the centre of town. Lavapiés and Antón Martín provide great Metro links. A taxi from the airport takes around 20/25 minutes. The apartment is clean and spacious, shower is hot and beds are comfy. The building is a little loud - we were awoken by neighbours crashing and banging very early in the morning a few times. Naza was super easy to communicate with and she provided plenty of great recommendations!