We were 5 co-workers staying here for attending a conference in Moscone Center (30 min walk, $10-13 uber/lyft or $2.5 tram).
Great communication and fast respons from owner and poperty manager. Check-in was swift. No physical keys, instead code lock. Which worked great and was very practical. The apartment was nice and clean and there were towels and bathroom amenities in abundance.
Since we didn't want to share beds, one of us had to use the fold-out sofa. Hence - "sleeps 12" is really to stretch it a bit too far, unless 4 of you are kids and the rest are couples...and you sleep 3 in all the king size beds. The king size beds were really comfy though with nice thick duvets. The fold-out sofa was to be honest far from comfortable, and he/she who sleeps there has no privacy. It also lacked duvet.
Wifi connection was good except from the 2 bedrooms facing the street where it at best was weak. Mostly non-existent. We had stronger signal from Taco Bell across the street. Heating and kitchen worked like a charm (even if the heater makes some noise, especially noticable for the one sleeping in sofa).
Unfortunately, due to electrical problems our apartment (and neighbors) had no hot water when we arrived...and for almost 5 consecutive days! I can tell you our showers were short. After some negotiation with the property manager we settled in a fair compensation, even though the owner put his "veto" and lowered the initial deal. Fair is fair though. Accidents happens. And they really did as much as they could in order for us to still be satisfied with our stay, despite the hot water issue.
All in all - its nice and clean flat. Nice location. Not a 5-star. But, since the SF hotel prices are what they are (especially during big convents), it is a good bang for the buck. We were also granted late check-out. Cudos for that :)