Also in SoCal, I get a mix of both. Usually two days, sometimes one, sometimes it says it is out for delivery on that second day but then they end up not delivering it.

From what I understand, the Amazon delivery people are contractors who are paid to deliver as much as they can. If they can't get to everything that day before 9pm, you don't get your package.

It has only really hurt me a couple of times where I ordered something for a trip, and it didn't arrive in time.