I visited on a work trip, but did some sightseeing with my wife also, and we really enjoyed our stay. Great location and neighborhood with plenty of cafes, restaurants, shops, etc nearby. As well as Castro you've got Dolores Park, Mission, Haight Ashbury, and other nice neighbourhoods not too far away.
It was a good flat with plenty of space for a couple, including outdoor space, good internet, kitchen facilities etc. and it was a clean condition when we arrived. Would definitely go back.