We had an amazing stay at Javi's !
First, the apartment is awesome, very clean, spacious and well decorated. The room is really big and sunny. There is everything you need ! The bed is gigantic and comfortable, there is also a couch and a desk. And you have your own big walk-in closet ! The kitchen is well equipped and practical. And the bathroom is also perfect and very clean.
The neighborhood is the coolest. A lot of cool shops, coffees, good restaurants and bars on Mission and Valencia. Some tips : try Tartine Bakery (just in front of the apartment), go to Bi Rite to do some healthy grocery shopping and have a cocktail at Elixir (oldest saloon in SF). There are also some major tourist attractions around : Dolores Park and the women's building for example and of course the famous mural paintings are just nearby. The Castro is at walking distance and you have a lot of means of transport available : BART, Muni trains and buses can take you anywhere.
And last but not least... Best host ever ! Javi is sweet and helpful, he was always there to answer our questions and to give us good tips on SF and California. And he's always striving to improve his guests' experience ! He asked us what could be add to the room, we answered 'a mirror maybe' and the day after : there it was !

I can only recommend Javi's place, it has everything : perfect room, awesome location and amazing host ! Go for it !