How much bigger is San Jose’s industry? Do you still see a lot of startups in San Francisco?
Nowadays, startups pay up the wazoo for a Palo Alto address. San Jose isn’t good enough and San Francisco is not part of Silicon Valley.
You don’t see many startups of any kind in San Francisco. Here is a recent NYT article about how unfriendly the city is to small business.
No offense, but you have 3 threads here asking about San Jose. I would suggest you make a trip west to visit the place for yourself. It will be a lot more meaningful than the advice from an internet chat board.
Also, it would be best to locate a job before you make a move. Once you have secured employment, you can consider which town or neighborhood will work best for you, given commute and other amenities. Tech companies and tech jobs are scattered all around the Bay and are not centered on any one area, so be flexible. Good luck!