We had a great time, it was close to public transport and we even walked to places like Union Square and the Haight-Ashbury district. Mission St feels a little bit dodgey on the first night, but once you get used to it, it's fine.
The apartment was really well equipped, and nicely furnished; the beds were a great size and it was great to have a nice big lounge room to sit and talk and wind down after a long day of seeing the city.
Brian and Leah were enormously helpful, left us info packages to make our stay easier and were really quick in responding to any queries we had.
Thanks so much! See you in San Fran again soon :)