I, personally, can't stand Big Train's Ice Rage its way too sweet, and seems almost gritty to me, but that could just be the thought of powder.
Some powder mixes are gritty and have a weird texture to the finished product other way too sweet. Of the ones we tested to date we liked Cappucine drink bases. We also like Pixie Mate, Jet's Mango Fandango (YUM, my favorite!!!) and we had a chai mix at the Atlanta show that we liked better then Oregon Chai.