I just tried this tea for the first time last week. Here’s my experience.
Preparation: I add one tablespoon of loose, coarsely chopped leaves to a large coffee mug. Then I run hot water from the tap (my tap runs really hot) into the mug. I stir and then drink immediately using a metal filter straw.
Taste: loved it instantly. Tastes a lot like green tea, maybe a bit earthier. Unlike green tea, it seems to be very difficult to screw it up. I can steep it all I want and it still tastes great. I never get that harsh bite that can happen with green tea that's been steeped too long.
Effect: like other caffeinated beverages, it gives me a boost, but somehow even drinking several large cups doesn't give me the jitters or feelings of anxiety that I often get from coffee. It's a much mellower, even relaxing feeling. I still love the taste of coffee and couldn't completely abandon it, but yerba feels like a much better choice for daily consumption. For me there were no mind altering effects other than the pleasant feeling I always get from a nice warm caffeinated beverage.