North CA has many advantages. As previously mentioned in the thread there are more tech companies that pay a lot more, and being from Irvine ya'll should be used to the housing prices. For RE investors, areas such as East Sacramento offered opportunities to buy low and sell high at 400% of purchase price. Yes, buy at $70K and sell at $280K. Can't say for sure we'll see the same RE cycle again, but if we do and you want to invest here make sure you have the cash to bid against other all cash offers.
North CA also have fewer people (vs South), a lot more water resources, and access to green rural areas (subject to wild fires, druggie burglars, and other hazards) with wildlife. It's much easier to find rural property in North CA next to a river, stream, lake, etc. that has water. If you're somehow forced to work in the city of SF, at least you can escape to a rural retreat on weekends, or round of wine tasting up Napa.
In the event of a natural or man made disaster, if the aqueduct or pumps stop running here in LA we're screwed. In North CA you're more likely to be within reasonable distance to a river with water in it. Fishing is also better.
What's not to like? Here is where your neighbors are sleeping, just to have a roof over their heads:
(For those who wish to help, google "The Gubbio Project").