> If you're just looking at caffeine intake you'd be better off switching from coffee to energy drinks

This is less true now than it used to be. I'm somewhat sensitive to caffeine and always look on the can to see how much is in it, and 150 is on the low side of most of the options available now-. 200 to 300 seems to be a lot more common among the brands that are newer than when monster and Rockstar first came out.