I stayed at the NH Arguelles for two nights over a weekend in August, during a visit to Madrid.
Arrived at the hotel slightly ahead of the designated check-in time, but were given a room straight away. Rooms are almost of 4* quality, with good furniture and carpeted throughout. Bed is probably one of the highest I've seen (a good meter from floor to covers), but extremely comfortable. Rooms are equipped with a plasma tv with some international channels. There was, however, no wardrobe, only a desk. Our room had functioning aircon (although a bit noisy) and, interestingly, a ceiling-built radio. Bathroom was excellent, with a power-shower.
Our package also included buffet breakfast, which was good although not much variety - just your usual cereal, toast, yoghurt, fruit and cake(s). It was a reasonable start to the day.
The hotel itself was of modern standard. Free wifi was available in the lobby. As far as location goes, the NH Arguelles is set in a student area not too far from the centre of Madrid, although not walkable. There didn't seem to be any buses near the hotel and the nearest metro station is about 5-7 mins walk away. Because that particular line was closed over August, our walk to a different line was a bit longer. As far as parking goes, everywhere around the hotel is residents parking, so unless the hotel provides parking itself, it could cost you a bit.
Finally let me just say that, although there might be a lot of graffiti in the surrounding area, we never had any problems either during the day or at night. In fact, we didn't have any problems or felt fearful at any point during our time in Madrid.
All in all, and for €80 for the two nights for two people, we were pleased with our choice!
PS: For those interested, the hotel had Pizza Hut room service!!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC