Mike's apartment is great. Easy to find and easy to access. Really clean and very homely - a lovely place to relax after a day's sightseeing, with plenty of good local bars and restaurants. There is a folder of recommendations for bars, restaurants etc which is very useful.
The location is great for all the major sites - we did the 3 main art galleries, all within walking distance so no need to use the Metro. I felt that the walking around the city gave a much greater sense of Madrid and added to our enjoyment of the city. (We left Reina Sofia gallery til last - 5 minutes from the flat, we could leave our bags there, catch Picasso's Guernica exhibition then cross the road to Atocha station and straight to the airport.)
I have no hesitation in recommending Mike's place and will happily return.