My own thoughts at the moment are:
I'm leaning towards Breed, with Farrell 2nd choice.
I don't think there are any bad things that happened that she had any power over, e.g. decimation of Downtown, homelessness, etc.
She's doing what she can, within the limits of mayoral power, such as organizing events to draw people downtown, but that particular problem will take many years to resolve itself, i.e. landlords have to be more realistic as to what they can charge for rent in the age of working from home.
More could be done, of course. The abandoning of Pacific Island Supermarket's plans to open on the empty Alemany supermarket building illustrates that.
But I think we're getting there.
And honestly I don't see how Farrell would do anything better, except be another white guy in the office.
His proposals basically boil down to "more cops" which is unrealistic because housing prices are so high in the city, and there's a shortage of people willing and able to do policework everywhere.