I was at Blue Bottle Coffee at the Ferry Building. I tried the machiato, and the "Gibralter," which is a super-short cappuccino/latte (photos #1 and #2). Their espresso is excellent: rich and complex.
I noticed that they use a naked portafilter with their espresso machine (see photo #3), which does not have spigots: the espresso comes out the bottom of the bare mesh. The barista explained that by using a naked portafilter, they can clearly see the process of extraction, and maintain perfect quality control. It's reflected in the quality of the espresso. Here is a write-up I found on the web that explains the benefits of a naked portafilter:
I'm interested to know if other cafes in the Bay Area use a naked portafilter, since I'm always on the search for baristas who are obsessed with quality and consistency.