Yerba mate is good stuff. Kind of exists like a middle ground between coffee and black tea for me in terms of caffeine/energy boost. I think it gets an unfortunate rep as being associated with "dreadlocked hippies" but in southern South America it's basically the common man's drink.
I think it kinda tastes like straw, but agree with you that when you compare it to the taste of coffee (burnt and bitterness anyone?) it's just as palatable.