Where I live, the water tastes and smells like chlorine bleach. My doctors told me often that I was not hydrating nearly enough. When Mio came on the market, I tried it. Now, I am well hydrated and happier. Because Mio contains no sugar, it does not affect my diabetes. I like being able to adjust the amount of flavoring in my water versus Crystal Light packets. WalMart and the grocery stores are now carrying generic versions, but IMO they taste like cheap Kool-Aid... yuck.
While I do understand that plain water is preferable, that is not always an option in some areas.
Mio is very good. My favorite flavor is the Lemonade flavor, though I've also tried Fruit Punch.
Still, I much prefer
True Citrus for any kind of water flavoring. They have lemon, lime, grapefruit, and orange, and it tastes wonderful. Nothing sweet, just a burst of fruity goodness.