2 LITER DESIGN: It looks tasty, almost like I'm going to have a an ice cream float or some sort of dessert. The Jazz is a great name. Sticks in your head after you hear it.
2 LITER DETAILS: I picked up the diet so there are 0 calories per serving. I'm not sure there is a regular version that isn't diet? It would probably taste the same anyhow because diet isn't a factor when it comes to taste anymore. They can fake anything with a sugary taste and keep it at 0 calories. Fact is, they could make everything Diet and you might not even realize it. Diet is more of a marketing technique to sucker fat people into thinking that soda is a good thing for them to drink and will help prevent weight gain (keep dreaming people).
PRICE: 1.49 at Safeway
WEBSITE: Pepsi.com is the company site. They didn't seem to be pushing Pepsi Jazz on the main site. You would think that they would at least have a small ad off to the side of everything else with something like "Brand Spankin' New". So I typed in PepsiJazz.com and up popped an official site and Jazz background music. Very nice. Not too much to the site yet but they do have their ad up.
TASTE: Both my wife and I thought the taste was almost like a light flavored coffee. As if this Pepsi Jazz version was to compete with Coke Blak in some way without the outrageous price. It's the French Vanilla that is doing that. French Vanilla is used in popular coffee drinks. Now I'm not saying it tastes like coffee, just reminds me of coffee. The flavor is good. It's not something I would drink with a meal. In a way, it's like a dessert drink or a drink to have after the meal or on a break.
AFTERTASTE: Nothing noticeable
SUSTAINED EFFECTS: Felt like picking up a saxophone but the feeling went away after fifteen minutes.
OVERALL: It's a solid entry. I can't say that it will catch on big. It's more of an amusement you would buy on occasion like you're out at the mall or sitting with your friends and you want something a little different than the regular soda. I can see kids drinking a lot of this but as an adult I'd stick to my regular diet caffeine-free Pepsi when eating or working.
WOULD I BUY IT AGAIN? Maybe. There are a lot of drinks I would buy first. Pepsi Jazz is more of a curiosity. That's why I anticipate that when the curiosity is gone this drink might not do very well.

GENERAL COMMENTS: I'll be interested to see if this stays on the market in the next year or if it will suffer the fate of Pepsi Blue and other entries that were curiosities to begin with but the buzz died down and boredom set in.