I have used the Primer/Driver and still use the Prime+/Drive+. It is worthwhile to note that these powders are high quality products that are designed to work around one's training. Thus, I like to use them strictly before/after my workouts, so as to conserve my supplies.
I think they all taste real good when mixed with milk (my favorite mix), but I didn't care for the taste too much when mixed with water. Also, they all mix very uniformly in liquid (a super nice feature--I hate powders that don't mix completely). And, they clean up easily, too. I have found that some protein powders cement themselves to the sides of my shaker, but not Primer/Driver or Prime+/Drive+!
Another nice thing is that these powders are low on carbs--which better enables me to get all the protein I need without consuming too many calories.