I just started using NUUN - mainly for 50+ mile rides or hot weather (high 80s F and up = hot for me). The lemon lime is decent and the watermelon seems a bit too sweet; neither turns my stomach as much as Gatorade.

My unscientific findings: 1. NUNN vs. plain water seems to keep my system flowing properly - no more four hour rides without a pee break. 2. This stuff has helped stave off the post-ride dehydration headache. If I start to get one after a ride, I use another one and it seems to clear up.