Leticia is a wonderful host. She's absolutely lovely, will spend the time with you if you need it, but if you want your space you'll have it as well.
She has great suggestions for what to do and see (she suggested Toledo given my appreciation for history, and it proved to be an amazing day trip).
I have to say that this was one of the best stocked flats I have experienced. The running joke I have with friends is that every flat I've stayed at has an empty olive oil bottle, but Leticia's place had two full bottles. It's a small thing, bit there's nothing better for me than having access to everything that you need when you need it.
The place is a bit out of the way from the city center, but it's about a 10 minute walk to the metro that will place you in the middle of Madrid in about 20 minutes.
While I didn't come directly from the airport to the place, getting back to the airport from here was the at all difficult.
All in all a really nice stay.