We stayed at Marta's place for a week and really enjoyed it. It's very cozy, bright and cute flat that has good location. In my opinion, this is the best solution for couples, but you can rent it if there are four of you.
The neighbourhood is suitable for those who need some peace and quiet. Nobody disturbed us during our stay. But you can find a lot of good night clubs, tapas bars and restaurants which are in 5-20 min walk. And it took us 10-15 min to get to Museo National Centro de Arte Reina Sofia and Museo del Prado, Atocha is also close to the flat.
Unfortunately, we didn't see Marta, but we chatted with her if we had any problems. She is very nice and hospitable.
This flat became an important part of our trip, so the next time we will probably book it again.