Simple, great tasting, and takes the guess-work out for most athletes. They also have the added benefit of calcium carbonate and magnesium sulfate with can prevent and even cure that gnarly acid/upset stomach many athletes get over long distances!

i'm not familiar with oral rehydration salts. i'll assume you mean endurolytes and or salt stick pills as they are the other way to get your electrolytes while exercising. this is a tablet like an alkaseltzer or an airborn. it disolves in a couple minutes by itself in your water bottle and it has a nice refreshing taste. since it tastes good i find myself drinking more and staying better hydrated. nuun has sodium (salt), potasium and magnesium in the ratios your body typically sweats them out. the pills are just a different form factor. nuun is much easier and more enjoyable. also you don't have to stop to drink get it out. it's in your water bottle so you just keep riding or running and drink while you go. no fumbling around with pills in a little container you can't manage. i have used nuun in 100 mile ultra marathons, expedition adventure races and long endurance cylcing events as my sole source of electrolytes and it's never failed me. i love it.I used NUUN on most of the Whereskarl Appalachian trail run, I never had to use salt caps, the NUUN in my Nathan pack was all I needed for electrolytes. Not having to think about taking caps was great as my brain was fried from running 40 miles a day.