I drink a bottle of GT's Kombucha every day sometimes 2 if I can afford it. Its the best. Expensive tho. I have a deal with my health food store and I buy a case of 12 mixed flavors for 35.00. Its a good deal.
I would not make my own because you have to be careful with mold issues and contamination. There are only 2 FDA approved distributors of Kombucha.