Everything was clean, relatively new and in good condition. Dani, his wife or his daughter were quick to courteously respond to any requests or issues.
It's in a great neighborhood, one of the best in the city, but fairly far from the tourist areas, if that's what you're looking for; however, the metro station is only a couple of blocks away.
For those with accessibility issues, note that there are rather steep, narrow stairs up to the unit.
Apartments in Madrid tend to be noisy; in this relatively quiet unit, the street noise was distant and only one neighbor could be heard on occasion.
There's a dedicated hot water tank. If you're OK with a 10-to-15-minute shower, as I am, the amount of hot water will suffice.
There's a clothes washer. Dryers are rare in Spain, and there's none here. There's a clothesline right outside the window for that purpose.
No breakfast is provided, but there is a coffee maker (Dolce Gusto brand) and pods.
Hope these specifics help. I was quite comfortable in the apartment for the month I was there.