A great apartment for its price - definitely a good deal if you're traveling with a budget. The host is very communicative as well and ready to help you if you have any questions. The only downside is that our cab driver told us it was an area where you have to be careful due to increased crime vs. other areas in Central Madrid. Whether this is true or not I don't know as it's my first time in Madrid but the area did feel a little dodgy at nighttime with people with poor intentions approaching you - but I'd assume this can happen everywhere. It was perfectly fine during the daytime though and it's not a problem at night if you are walking with a friend or taking a Uber home.
Overall, a good experience, and an excellent host. I'd definitely stay here again with a friend if I had the chance.