You won't regret staying in Marlen's apartment because it is really great. It is really modern, clean and stylish, and everything works great. There are several excellent restaurants in the street, and it is really close to Gran Vía and most of the attractions in Madrid could be made by walking. It is also worth mentioning that Marlen is a very nice person and offered to book attractions or taxis when needed, which was awesome. Ah, and the apartment has a lift!! you won't need to go up with a heavy luggage ;) The only downside is that the boiler is small and it means you only have hot water in the shower for 10 minutes, but I have to say we were in 3 people and we had no problem at all. Quick baths, around 30 mins wait and it was ready for the next. This place is HIGHLY recommended, 5 stars!