I have all of my windows tinted to the maximum allowed capacity! (It was a gift from my husband, I wasn't really specific on what I wanted and he basically chose the specs for me)
I also live in So Cal. It definitely helps protect your skin and the heat from the sun especially!
Before, when my windows were not tinted, my car would get so hot when parked outside (and I have a white car too). Now it feels so much better.
Driving at night isn't really an issue. I was initially concerned about that too, but I don't feel incapacitated in any way. Also, I realized it actually really helps with all the car lights from opposite streets. Because of the tint, the lights from other cars aren't that bright and don't hurt my eyes as much.
Highly suggest window tint. It also prevents people from being able to easily see into your car and potential break-ins!