I literally just got my MCU2 2 days ago and this update came out. I praise to everyone who was hanging on when the rear camera was dark. But the upgrade was one of the best things I've done to the car. It makes it feel like a brand new car. Now that the price dropped to $1500 it should be a no brainer
I had just bought the Abstract Ocean license plate LED bulbs to help the situation out with a little more light back there, and will install them, but it is back to the brightness I was used to on my AP1/MCU1 car.
I've noticed a lot of variability in brightness. The side cameras still are might brighter in the same lighting conditions. I don't know why the backup camera image can't be processed in the same way other than backup cam is full color fisheye but AI shouldn't care.