Let me get this out of the way right from the outset: There is one brand of bottled coconut water that is hands down, without question, far and away, not-even-in-the-same-game better than any other. Harmless Harvest's coconut water is the best bottled coconut water you'll get without lopping off the top of a nut with a machete yourself.
It's a tad sweeter than most of its competitors, sure, and it has a really nice savory background, but that's not what makes it great. It also has the most intensely nutty flavor with a complexity that its competitors lack, but even that's not its strongest selling point. What sets it apart is its fresh taste. It's the only brand I've seen on the market whose water is 100% raw. Rather than heating their coconut water to pasteurize it, they use a high-pressure, low-temperature method that produces coconut water that's completely safe to drink, but is still 100% raw.
Where every other brand loses complexity as volatiles and aromatics are broken down during pasteurization, Harmless Harvest maintains it. A side effect of this production method is that at least half the bottles of Harmless Harvest have a distinctly pink/purple hue thanks to high levels of antioxidants. I'm not one to espouse the health virtues of antioxidants or worry about nameless "toxins" in my body, but if you are, then this visual display of antioxidants should be another selling point for you (for my part, I've noticed no flavor difference between pink and clear batches).