The location is very central. Close to the metro and walkable to the Atocha train station. The rooms are new and clean. Our room had AC. The hotel let us check in early without any issue. Giving it a 3 star because the walls are thin. We stayed here 4 nights and one night we had a hard time sleeping because the neighbor had the TV on all night. Other than that, this was a great place for us for we only needed a basic room to stay in Madrid while we explore the city day and night.

I had a triple room in this hotel, I found it a compact and viable option, the room was clean and air-conditioned. Most importantly it's location just of the main square (SOL) made it easy to find and easy to explore Madrid.

Free Wi Fi if you went and sat on the first floor dining area and the staff were very helpful.

We opted not to buy the breakfast with the hotel as it was cheaper to go outdoors with lots of options about but I would stay here again for convenience since it was clean and located in a good place.

My mom and I stayed at the Eden Neptuno . We read the reviews previously and the fact that it was in the center of everything we booked it...The hotel has all the basic things you need. It is not a five star hotel but it isn't a hostel either. We had a very clean room with above average furniture, the bathroom is very nice.I was a little surprised , because when you see it from the outside, and the small lobby, you are thinking the worst, but it was a great surprise. All the sight seeing, shopping ,and food is walking distance , even the free shuttle that takes you to the airport...the only bad thing is ,since it is in the center of everything , the city never sleeps....so if your room is towards the street, you may have to be a heavy sleeper because it can be pretty loud,The room has a small window that you can walk out of and enjoy the scene....don't do the breakfast there , it isn't worth 5 euros...but I would stay here again , especially if you are on a budge but you are also used to the finer things in life .

I stayed here with a group of 13 friends in mid-June 2011. Overall, we were very pleasantly surprised with the hotel.
It has a great location just a few seconds from the Plaza del Sol. This is a great location to stay in if you want to walk around Madrid, as from this location, we covered pretty much the whole of the city. There are great bars and restaurants nearby, you can walk to Retiro Park or Plaza Mayor, and the subway is just seconds away too if you want to go further afield. The hotel IS on a street which is part of the red light district, but we had no problems. Apparently it can be a bit noisy if you have a room that faces on to the street, if this bothers you, just ask for a room which faces on to the inner courtyard (no beautiful view but fairly quiet).
Do be careful of your belongings around here, because there are a lot of pick pockets operating in the area. However, we had no problems whatsoever with the hotel.
The rooms are basic but clean and comfortable, with generally good bathrooms.
Overall, this is a basic hotel, but great if you want a cheap city break in the centre of Madrid.