Diego's place is bigger and nicer than we expected. We had trouble contacting Diego to let him know we were on our way and when we finally connected, he told us he'd meet us in 15-20 minutes, which he did.
Diego left us several goodies like coffee, tea... as well as shampoo, conditioner and facial wipes. It was great to hear from him during our stay asking us if all was ok and we needed anything. I contacted Diego even after we left as I had forgotten several items, and he was excellent at getting back to me.
The roof top terrace was a great addition to have; we had our breakfast there each morning. It was great to have a TV (even though we didn't watch much but were able to play radio and have music). Apt was clean, quite large for a 1 bedroom and best of all on 1st floor.
I was a bit concerned about the neighborhood after hearing from some Spanish friends that it was seedy and dangerous. None was true. The neighborhood has great shops and a wonderful restaurant next door-La Pescaderia - has great vibe like Village in NYC. It was safe to walk even during late nights. We walked everywhere during our stay; Metro stations are also nearby.
I would definitely stay at Diego's again when visiting Madrid.