The only good reason to buy in the Bay Area is to be able to control the property. Buying homes as an investment is risky anywhere, but it's especially stupid around here for most people, simply because the expected ROI is so much worse for a given sum of money than can be had in almost any other investment. Only the super (top of the top 1%) have any business putting "home ownership" and "investment" in the same thought for this area.
In other words, your investment grows faster. If you can afford to buy and plan to sell in 2-3 years you can probably make much more money in the Bay Area than in somewhere else.