All this talk about how high prices are, I remember when I bought a candy bar for a dime but that was then and this is now. Food inflation is effecting everyone especially restaurants, and I disagree that Jamba charges too mich. I do, however, agree that they need to overhaul their in-store experience completely.
I'm going from recall here. They started in late 2010 with 20 test stores in the Sacramento area. In approximately May, 2011, they added 100 stores in Southern California. They announced on the latest conference call that they would be adding 15 - 20 stores in Northern California during Q3 and Q4. I personally know of at least 2 in my area that have it (Pleasant Hill and one Walnut Creek Store). The Lafayette store does not have it, I am guessing because the frozen yogurt store already open in the strip mall has a clause in their contract that prevents competition.
I might suggest searching the phrase "jamba frozen yogurt" on Twitter from time to time. For that matter, you can search "jamba" plus basically anything else you want (coffee, oatmeal, breakfast, energy, kits, etc.). You get an unedited stream of comments regarding the item in question, and therefore can get a pretty "raw" look at public comments, for good or for bad. For example, you will notice overwhelmingly positive comments on Jamba's oatmeal, and typically either no comment, or negative comment, on their coffee. It is really quite the helpful tool, I use it a lot.