High caffeine and with a primarily grassy taste, this is a good energy caffeine, but not quite a replacement for a good, strong breakfast black tea.
For what it is, straight green mate pretty enjoyable. On its own (with 4tsp brewed in my 2-cup teapot), its got a moderate strength of flavour, closer to a green tea than a black in robustness, but I feel less afraid of overstepping than I would with tea proper. I love mixing this in with less caffeinated things when I want to give it a bit of a kick — it tends to blend with other teas well.