While San Jose pales in comparison to San Francisco, as a Bay Area native I've always enjoyed Santana Row, some parts of downtown (near 1st Street) and some of the outskirt cities like Campbell and Los Gatos. The only thing about the South Bay is that since everything is so spread apart, cab/uber rides are a bit pricier than SF.
If you're in town for Startup School, I highly recommend journeying up to SF afterward.
If you're in town for Startup School, I highly recommend journeying up to SF afterward.