Diet Barq's Root Beer: Thumbs up. It's a different root beer flavor than Diet A&W--my guess is, Barq's is sharper (hence the slogan "Barq's got bite"), while A&W is creamier and not quite as strong. Bottom line, Diet Barq's is chug-worthy. There's only one reason why it took so long for me to try this soda: My local grocery stores only make certain sodas available in cans but not in bottles, which sucks because the per-ounce price for soda in cans tends to be much more expensive than soda in bottles***. Diet Barq's Root Beer is one of those sodas.
Diet Sierra Mist Ruby Splash: Thumbs WAY up. I like this a lot, partly because I like grapefruit-flavored sodas like Squirt and Fresca, and adding some grapefruit to Diet Sierra Mist is a home run for PepsiCo. The lemon-lime Diet Sierra Mist is available in both 2-liter bottles and cans, but for some reason, like Diet Barq's Root Beer, I have only ever found the Ruby Splash version in cans.
Kroger Diet Big K Citrus Drop Xtreme: On the fence (but only because, as I mentioned back in Volume 6, Number 9, I was never a big fan of Mountain Dew in the days when I drank "regular" sodas). I would drink it if there was nothing else in my fridge, but I can name 20 diet sodas I like better. That said, I suspect that if you like Diet Mountain Dew, you'd like Diet Big K Citrus Drop or Diet Big K Citrus Drop Xtreme.
Walmart Diet Dr. Thunder - On the fence. At least it didn't insult Dr Pepper the way Walmart's diet root beer offering insulted Diet A&W and Diet Barq's. But for what it's worth, it's not often that I go to Walmart for anything, so there isn't much point in buying a soda when the only place where you can return the bottle is a store you don't often go to.
Dr Pepper Ten - Thumbs up. This tastes even more like regular Dr Pepper than Diet Dr Pepper does. Maybe a tiny little bit of high fructose corn syrup (10 calories per 12 oz. serving) makes a big difference. I wonder what Cherry Vanilla, Cherry Chocolate or Raspberry Creme versions of Dr Pepper Ten would taste like if they existed (these are all varieties of Diet Dr Pepper than used to exist but no longer do).
Diet Coke with Cherry - On the fence. Not to be confused with Coke Cherry Zero (which I like). I liked it, but not quite as much as Coke Cherry Zero.
Coming soon: Diet Mountain Dew Code Red. I bought a 12-pack of this at the same time that I bought the 12-pack of the Diet Sierra Mist Ruby Splash (it's yet another soda that I can only find in cans but not 2-liter bottles).
One more thing: I mentioned the Coca-Cola Freestyle Machine over a year ago. Now it's available in many more locations, including several in Michigan, the closest of which is a burger restaurant in Auburn Hills (about 20 miles north of me). And earlier today, Coca-Cola announced that it would install the machines at over 800 Burger King restaurants (note: that's only restaurants owned by BK, not those franchised by BK). The dream of tasting Coke Orange Zero, Coke Raspberry Zero, Coke Lemon Zero, Diet Barq's Vanilla, the various flavors of Sprite Zero, and a 50/50 mix of Fanta Cherry Zero and Fanta Lime Zero may come true in 2012!
*** For example, you might be able to find a 2-liter bottle of your favorite soda on sale for $1, which is 1.48 cents per ounce; you're lucky if you can get a 12-pack of cans of that same soda for $3, in which case it would run you 2.08 cents per ounce, which is over 40% more expensive.