anyone with a sensitive stomach may want to check the label on these products for artificial sweeteners... sugar alcohols are a natural GI irritant, and are tolerated by most people, but if you have a sensitive stomach (like i do) they can lead to bad abdominal pains. found that out the hard way, i was on a ride with friends and one of them gave me a Nuun to put in my water. i threw up a few minutes later and had horrible stomach cramps the rest of the ride, found out after we got home that it contained artificial sweeteners.
what i started doing is keeping small packets of salt in my jersey pockets, pop one every 30-45 minutes (depending on ride length, intensity, temperature, etc) and wash it down with water and have a gel of some sort to get the salty taste out of my mouth (and a few calories as well).