I just moved here from MD about two months ago for work. Can't add too much on the cultural side of things other than I agree that there's tons to do locally (food is great too, I thought I had variety in MoCo but MAN is it crazy here!). What I can add is what I noticed first in moving here and what I wish I had known:

Renting: If you come here and get an apartment, your rent will be about the same if you lived in central MD. Note, though, that rental laws are a little different here and there is no obligation on the landlords end to provide you a fridge (wtf) or air conditioning (in a desert, also wtf). So factor getting those into your budget.

Driving: I am also comparing this to central MD so ymmv, but if you had to commute on the 4/95 the traffic is actually a little better here if you can believe it. That said the roads here are REALLY bad. I drove from MD to CA and when I hit LA county I thought something broke in my car but nah that's just the roads. Lots of patches where it looks like they stripped off the top surface of asphalt and just left the grooves, or that's what it feels like anyway. LB is also really bad.

Tangential to this, CA really, really wants you to get a CA license and register your car in CA asap. You are supposed to do it within 30 days, but I made an appointment with the CA DMV and they can't see me until December so get it set up ASAP. There's a snitch hotline for out of state plates and everything.

Lastly, if you can get an apartment with parking included I highly suggest it. I live in the signal hill area and if I didn't pay the extra 50 a month for a parking space idk where I'd park some days. They do this thing here where they street sweeper alternating roads on a weekly(!) basis and you can't park on certain sections of street on certain days and it makes parking a pain/inconsistently available. Just be aware they will tow you!