Well I usually drink RedBull whenever I want a drink other than water, orange juice, or alcohol. I saw essn's Energy at Costco a few weekends ago, and figured 20 bucks for 24 of them was considerably cheaper than RedBull, which is about 35 for 24 at Costco. I liked the packaging and look of the bottle, and it seemed to be a nutritious, natural drink with some good stuff in it.
I've finished about half of the box so far, and haven't had any bad tastes yet. The flavor is very unique, and tastes like a strong green tea, with some tart and sweet flavors in it. The energy gained from each bottle is noticeably, but not overpowering, like RedBull sometimes is. It's more of a slow, sustained energy for 2 to 3 hours that I can feel, and keep me going at work, or wherever.
Although it doesn't give that sharp, immediate, and extremely powerful RedBull boost, it does last for a long time, and seems more like sustained energy increase over several hours. There is also no crash involved, and the energy seems to dissipate as you go through the day. I like this drink quite a bit, it's not the same as RedBull, but it serves a different purpose as an energy drink that can keep you energized without the risk of crashing from drinking it!