Coconut water has a lot of potasium but not much sodium. Wrong electrolyte profile.
http://www.theatlanticwire.com/natio...ood-you/40954/
http://www.forbes.com/sites/robertgl...t-water-craze/

The three major brands are owned by megacorps like Coke and Pepsi. It's triumph of marketing- getting people to pay big bucks for what was a waste product.
It's also nasty tasting.

I have used Hammer HEED but it does not agree with me on rides over 5-6 hours. I'm trying Skratch Labs now. I prefer drinks that are not very sweet- after hours riding sweet stuff does not taste good. I find it difficult to get even half a Coke down.

For rides under 2-3 hours I eat a good breakfast and don't need calories on the ride.