Amazing place to stay in Madrid! Close to restaurants, grocery stores, shopping, metro and bus lines. We actually found that we didn't use the metro all that much though because the apartment was walking distance to the Royal Palace, the Cathedral, Plaza Mayor, Plaza de Sol and really most everything else you will want to see. The only time we used the metro was to go to Santiago Bernabeu to see a Real Madrid match, and once when we didn't plan our route very well and wanted to visit two sites on opposite sides of the city in one day.
The apartment itself is lovely. We especially enjoyed sitting on the balconies and watching the world go by. Inside is comfortable and pretty roomy for an apartment in the center of a major city.
We especially appreciated that there was coffee, sugar, tea, salt, pepper, oil and vinegar (plus other stuff) available in the kitchen. Plus, we arrived just as they were finishing cleaning so we were given a nice full tour of the place - and - the person who greeted us returned a few minutes after she left and brought us a bottle of wine! Very nice personal touch.
All in all this is definitely a great place to stay. It is a little noisy, but that is because you are in the heart of a busy city. You aren't going to have such a close-to-everything location like this anywhere without your basic city noise.
We will most definitely chose to stay here again if given a chance when we return to Madrid!