If I could only choose one, go for the Malbec. It's a unique grape that excels in S America. Thats one of the varietals that do best there. What is your source for the juice? I picked up my chilean juices a month ago and they have just finished secondary ferm. I guess as long as the buckets stay cold, they're ok.
Varis, I agree with Gr8zins and if you are only buying one, I would go for the Malbec. The juices that your HBS has have been around for a few weeks. If they have been kept refrigerated and have not started fermenting, they should be okay. Don't be too surprised if you get a low initial SG. That would indicate that fermentation has begun.
I bought a pail of Malbec and another of Cabernet Sav.
These juices really have distinct flavors.!! The Malbec juice tastes a bit to malt or I don't know but I liked it.
Added yeast energizer (around 2tsp) and yeast nutrient (around 4tsp) on each pail.
SG won't be accurate since it was pre-inoculated but measured at ~1.085 on each.
Added some american medium toast oak chips that I bought.