The Mayerling might not be too flashy, but it's certainly good value for money! It's in a great location of town, very close to a metro station and bus stops, and in a very lively and varied area, with lots of bars, restaurants, supermarkets, bookstores, shops of all kinds, museums, theatres, etc. at walking distance, and a stone's throw away from the city center. There's a vegan restaurant almost next door, as well!
They offer a good breakfast, included in the room price, and free coffee and tea all through the day from their reception area, with extra cookies or pastries most times. They have comfy seats and tables there which makes it a great place to sit and work on your laptop if you wish to, too. The rooms are simple but very clean. The staff was down-to-earth and friendly. I felt very comfortable, safe, and welcome, and I'll most definitely consider staying there when I'm in Madrid again!