Well after a couple more days of drinking Celsius, both WorkingData and I decidedly (independently) to call the whole thing off.
I experienced the diuretic effect *everytime* I drank the stuff and I did not like it. Or having to pee all the time. Plus when I poured it over ice, the foamy head was a sickly blue-green color. Ick. Too bad I don't have a picture.
WorkingData reports the Wild Berry flavor to be even more sickly sweet than the Cola. Plus it stained his mouth a reddish purple and required a few tooth brushings to remove.
We have taken the remaining bottles to the kitchen for other brave souls to try. That is if we run out of Nestea and Diet Dr. Pepper.