If I could change your mind ... consider Boston instead. Here is why:
I looked at your LI profile and noticed that you're in London, attending Hult, and in mobile tech space.
San Francisco is very expensive, with it being the Hollywood of innovators, it's becoming crowded. Don't get me wrong, it's a great place with lots of opportunities, great minds, and a great community. I love SF area. Having said that, Boston can offer a comparable experience and opportunities at a much lower living expense and closer to Europe. It's also home to Hult International and many other great colleges (Harvard, Babson, Bentley, MIT...).
If you're not convinced, then I recommend that you take a trip to SF area and attend some career networking events and conferences. The best way to approach career opportunities is to meet people in person.