The flat is clean and tidy. You will find everything you need for a short stay. Raul is a great host and will give you great tips on where to go in Madrid. The location is great (LaLatina), very central and one of the best and cutest area of Madrid. It's on 4th floor but there's a lift. The flat was interior, which means no view on the street, for me that makes it quieter for work. There's good Internet connection and didn't have any issue while working in the flat when needed. Didn't have any issue while staying there, everything was in good standard/shape and useful: several towels and adaptors you can use, etc...
Will definitely recommend the flat.