I just auditioned Via on last weekend's trip and confess I'm impressed at how good it is for so little weight and fuss (other than buying it, that is). I prefer the Italian roast–not a surprise since I drink espresso at home. The Colombia is a little less distinctive, but still fine when I use less water.
By comparison, Java Juice has a winey (mildly acidic) finish like some Central American and Indonesian blends. A single serving makes more when made to a comperable strength. Both Via flavors have a smoother finish. Via also seems to include some solids in the brew while JJ is completely filtered.
I can make a case for either–it's great to have two choices for single-serving instant that both taste like coffee. I'd love it if both companies expanded their coffee region options so we, the picky could dial in our specific tastes.
Before that happens Starbucks will have to decide their experiement is enough of a success to keep making the stuff and getting it into more stores–something we can't presume, given their love of flinging things at the wall to see what sticks. If you like it, it wouldn't be a bad idea to stock up.
My challenge to Java Juice is to counterpunch by introducing a kickbutt French roast (find the hidden mixed metaphor).
Cheers,
Rick