We booked at relatively short notice after our original hotel choice became unexpectedly unavailable - despite that we were still able to get a good rate on the Eurostar hotels own website. Direct bookings on the website also get you included breakfast, complementary mini-bar and late check-out.
Location was perfect, right in the middle of the city and within easy walking distance (< 25 minutes) of everything we wanted to see (including Plaza Mayor and the Prado, Thyssen and Reina Sofia galleries, as well as being handy for the Atocha station and the Retiro park).
Our room on the 5th floor of the "A" block was exactly as advertised, modern, very clean and comfortable with a very nice king size bed as specified. Minibar contents included several cans of soft drink., water and some cans of beer. We also had a bottle of very reasonably priced Cava sent up to the room. Large screen TV with (limited) English language channels and functional free wifi (which only required registration once during our 5-night stay). We were pleasantly surprised how quiet it was at night, even with our window open. I'd expected it to be noisy given the central location, but we were only minimally aware of outside noise. The a/c seemed to only be on heat (usual set up for Spanish hotels in the winter). As we like a cool temperature, we opened the windows to the extent possible and brought a small portable fan with us.
Breakfasts were very good, fairly limited selection but good quality and the coffee was excellent. Even the scrambled egg and bacon was good - a surprise in a continental European hotel!