My wife and I had a great stay at Miguel's apartment in Madrid. The location is very central (about 10 mins walk to main metro station Sol). The apartment is on the 2nd floor of a very busy street, there is a security door and a porter, so it's very secure despite the busy location.
Miguel was a great host and met us downstairs at the agreed time. He took us up and explained everything (in spanish!) Lucky my wife speaks some spanish or it would have been a bit difficult :) Miguel left a bottle of wine, some fruit and bottled water which was a nice touch.
There are 2 air conditioners (one in living and one in the bedroom) so we managed to keep very cool all the time. Air-con in the middle of July is an absolute must!
Be aware that the apartment is located above a small plaza and there can be some noise from the bin collections late at night. Also starbucks (directly below) was undergoing major rennovations during our stay and was a bit noisey.
All in all we had a great stay and wouldn't hesitate in recommending to others.