All of the prebottled tea you'll find at a store contain either sugar or artificial sweetener.

You can buy individual tea packets that you steep in hot water, which is the healthier option. (Don't get lipton tea bags, it taste like shit)

I personally love bitter drinks, I drink espresso black, but I wouldn't recommend you move from soda to black tea. Get like Earl Grey or a white tea, both of which taste great on their own.

Switch to tea. There's a wide variety of different types and flavors avaliable, so if you don't like one there are hundreds of options.

Many are purported to help with weight loss, helping curb hunger (which is something caffeine itself does, but many teas have other properties that help with hunger)

Just don't get in the habit of adding sugar. I occasionally like honey in my tea, but it's a rarity, usually when I have a sore throat or allergy issues.

"I just tell it like it is"