The location is absolutely amazing; nearly all the tourist-y places you might be interested in, whether its the Plaza Mayor or the Royal Palace or the Retiro Park are a short walk away or an even shorter metro ride away since the Sol station is right there! There are plenty of places to eat, shop, and do anything else you might be interested in.
The apartment itself is clean, well-stocked in terms of towels and bedding, and coming back after a long, sweaty day to an air conditioner and a shower with amazing water pressure was a godsend. Highly recommend this to anyone visiting Spain, regardless of how long or short their stay is!