Diet Coke > Diet Pepsi, imo. Growing up in a household with a type 1 diabetic father, I became a diet drink aficionado. Diet Pepsi has definitely come of age in the past few years, but back in the 80s, diet Pepsi was comparable to Raid or some other aerosol bug spray and I just can't get that out of my head. Now, the diet cherry Pepsi is pretty good, however the cherry Coke Zero is probably the best diet drink around.
Also, as far as I know, Kroger doesn't own Safeway. I just looked at the Kroger site and it's not one of their listed brands (Ralph's is though).
Edit: AoC sounds pretty cool. The day/night aspect sounds interesting.