After staying in 10 hostels in the last 2 months I can say this was definitely one of the best. It's in a beautiful old building (where else will you find a hostel with a marble courtyard, fountain and potted flowers??), right in the heart of downtown Madrid, a 10-15 minute walk from Atocha station. The security is very good - you need your magnetic keycard-thingy to get in past the reception, then the same card for your room and locker (admittedly figuring out how to open the room and locker can be a pain, though). A typically small Latin-Europe breakfast (croissant, juice and coffee - although I noticed someone ask for cereal too) is included in the price. The staff is friendly and helpful, there's a full bar, and even a club downstairs - great for solo female travellers who don't want to walk around at night looking for a place to hang out.Some of the downsides: the rooms are very small and they really pack in the beds; on the other hand, the lockers are large enough for most people's backpacks. (Not mine, but mine is enormous.) The shower I had was lukewarm, and there was nowhere to hang clothing or towel in the tiny stall. Free internet is advertised, but not yet available (they opened 2 months ago and don't have computers yet). Some people might find the breakfast pretty meagre. But overall, I'd say for the price of 15 euros, it's a great place to stay!