Stayed in October for a 3 night city break. Madrid is a fantastic city and the Arosa is well situated to enjoy the sights and to visit some of the great food establishments nearby. The hotel is currently undergoing sandblasting of the exterior so is covered in scaffolding and the balconies (in rooms with balconies) are 'unusable' as a result. Ordered fruit and Cava in the room prior to arrival which was correctly arranged and was a fantastic collection of fruit that lasted for the stay!!
There was some noise from other rooms as the soundproffing is not fantastic but the higher floors did not seem to suffer greatly from city noise although it was present - possibly more noticeable on lower floors. Room perfectly adequate, air conditioning satisfactory, good bath room.
Staff were OK although had little interaction.
Breakfast OK - can be busy in a small area of the lobby / lounge.
Wi-Fi was free but connection / speed was patchy.
We would not have used the Gym but were unaware there was one as it does not seem to be promoted / mentioned.
The much commented lift has to be the smallest (and triangular) cabin ever - max 2 people, no luggage and cosy!!)
Starbucks opposite hotel was great whilst waiting for the tourist bus or just for the twice daily fix!!

We stayed for three nights between Christmas and New Years. The location is great and walking distance to all the sights we wanted to see, plus getting there from the airport on the subway was easy. I had read other reviews about a noisy elevator and the first night we were put in the room with the noise. I could literally hear the elevator going up and down and I woke up several times when the elevator banged to a stop or when noisy people came out of the elevator late at night. We asked for a change of room and the staff changed us to a better room without any problem or hassle. The second room was much better, from decor to a bigger bathroom and more space. Overall we thought the staff was helpful and we appreciated being changed to a better room.

The Pro's - The location is within walking distance to the Parque del Buen Retiro, the Palace, and the Plaza Mayor. It is also just around the corner from Puerta del Sol which is a very lively hub of activity after dark (though you should probably be careful about going out on your own too late here as there are some unsavoury characters). Free minibar (but then hotel is expensive, so it all balances out).

The Con's - We picked this hotel as it was a Best Western and we stayed in a number of their hotels on this trip, all of them lovely, except for this one.This is not a 4star hotel - perhaps a 3 (at most).
Breakfast was terrible - sloppy scrambled eggs,chewy tough bacon which appeared to be 2days old and extremely sour milk in the coffee machine.
Parking is actually offsite in a public parking station which is dark, dingy, and quite frankly, scary - not to mention, expensive, at 27.50euro overnight. The lift, which claims to be uniquie (it's triangular shaped), is actually small and completely useless (can only fit 1 person, no luggage). Rooms are dark, dingy, old, not very clean, and most definitely not soundproofed.
Worst of all, however, was the fact that reception staff charged the credit card we used to secure our booking though booking.com, before we had even checked out and without gaining our authorisation. The biggest problem with this being that we had advised at checkin that we had an international prepaid travel mastercard and would be using that to settle our bill. Instead, we had to pay not only the totally unjustified room rate, but a quite hefty international transaction fee as well. Very rude and presumptuous.
We will definitely not stay here again.

Just back from a 3 night break over Xmas and to be truthful it was a bit disappointing! Arriving mid evening, finding the hotel completely covered in scaffolding and a huge advert for Vodafone! This just about blocked any view you would expect and outside the windows were workers walkways. Thankfully it was the Xmas break so there was nobody working at 8am...

The bar was deserted, traffic noise on the Gran Via rooms was loud, breakfast was dull, drab and basic, the lifts were tiny and took an age. But on the positive...great location, right in the centre of town, everywhere is within walking distance.

There must be better hotels in Madrid and while the works are on-going I'd recommend staying somewhere else.

We spent little time there as it was a little depressing so I can't comment on the helpfulness of the staff.

A bit of pre-warning from hotel management that there is long term work in progress would've been very helpful, upon arrival we had a sinking feeling that it wasn't going to be the break we'd planned/hoped for.