It's still not great for you. The "power" drinks like Powerade and Gatorade have a lot of salt in them because they are meant for athletes who are working out so hard that they deplete their salt intake through sweating. Unless you're doing hours and hours of football drills or the like, Powerade should not be your source of hydration.
If you drink Powerade Zero all day long, you're going to probably double (or more) the amount of salt you need in your body... A person's daily intake of sodium is supposed to be around 2000mg, so drinking 7 Powerade Zero's a day will be about 1050mg of salt- and you haven't even begun to consider all the salt in the other things you ingest in a day. Salt is something our bodies require in moderation, but too much can cause blood pressure problems, and heart and kidney issues.
Stick to water. If you're REALLY sick of the taste of plain old water then in infuse it with some fruit - make cucumber water, lemon water, rasberry water... you could probably even infuse your water with grapes if you like the taste of grape. More flavor than plain water, and a much kinder drink for your body.