Ruben made our arrival very easy thanks to his wife that has a shop very close to the apartment.

The flat was very clean and offered everything we need. It was a bit smaller than we thought, but it was more than enough for the two of us.
Its location is very good, a few minutes walk to Union Square. We were working at Moscone Center and it was also easy to walk there (15mn) in the morning (a bit harder in the evening as it's almost on the top of the hill! ;).
Many cool restaurants in the street, including classic diners for breakfast a few steps away.

Conclusion: We had a very nice stay in Ruben's apartment