I drink the stuff all the time, because it doesn't give me the jitters the way coffee does.
I don't make it the traditional way, I usually just brew it like loose tea: I put a few teaspoons of the dried leaves into a tea pot, and and let it boil. Also, I usually leave it simmering for a while before I pour it, it helps infuse a stronger tea.
It reminds me of green tea, in terms of flavor -- not unpleasant, but not something you're likely 'used' to drinking. I got mine from mysips.com and it's cheap as hell. Takes a while to get through a pound.
As for its comparison to Spike: not so much. Same type of clean stimulant, but, IMHO, not nearly as effective (this might be psychosomatic, though, too).