Diet Rite is sweetened with Splenda (Sucralose) and Sunette (Ace-K.) It is basically Caffeine Free Diet RC. If I remember correctly, Diet RC [which I have yet to actually find anywhere in Florida, Georgia, Alabama, or Texas] is sweetened with Splenda Only, but contains Caffeine. Diet Rite availability varies by area.

I've found the best areas to be North Alabama (Hartsel) and Central Texas (Waco,) where I actually found it in Soda Machines as well as in 20 oz. Bottles. I've found the 20 oz. Bottles in Central Alabama (Montgomery) and South Georgia (Baxley,) but no Soda Machines. In Central/South Florida (Leesburg, Tamarac, etc...) they have the 12 packs at decent prices, and put them on sale reasonably frequently. Up here in NW Florida (P'Cola,) you'll NEVER find Diet Rites on sale, and 90% of the time everyone is sold out of the 2 Liters [most likely because they cost half as much ounce for ounce as the 12 Packs.]