Question about monster energy!?

how long does it take to kick in? and how long does the boost of energy last do you think? im drinking a new one.....half tea, half lemonade. its called monster rehab! its really good, non carbonated, only 20 cals. OH and another question about monster...are the sugar free ones bad for you too? i know they have a lot of caffine and whatever taurine, and ginseng are....but are they THAT bad?