most teas have many benefits for your health. All teas (true teas.... red/black/green/white) contain polyphenols (a type of anti-oxidant). The less processed the tea, the better it will be for you, and brewed teas (hot or cold) are better for you than instant (powder) ones (loose leaf is generally best). White tea has the most anti-oxidants, and is least common, least processed and tends to be most expensive. Black teas are the most processed and most common, and have the least health benefits. All teas contain catechin polyphenols that raise thermogenesis potentially by up to 4% (the rate at which calories are burned), and have anti-cancer properties. White tea is generally the best one for you, and black/red-oolong tea/green/white all come from the same plant, just at different stages of plant growth and fermentation, and involve different processing (the less processed, the more anti-oxidants and other nutrients the tea retains). Rooibos teas come from a different plant all together, and really aren't a true tea, but it has no caffeine, and no oxalic acid (true teas do contain this), so it can safely be consumed by people who are prone to kidney stones.
Studies have seen connections (the good kind) between tea (true tea) consumption and skin health, cancer, the immune system, diabetes, weight loss, cardiovascular and bone health.
Rooibos tea also has been shown to have benefits, including, anti - spasmodic agents, which can relieve stomach cramping and colic in infants, as well as aiding in health problems such as insomnia, irritability, headaches, nervous tension, and hypertension. It is also shown to help boost the immune system.
Like most things to do with eastern medicine/naturopathy, western doctors/scientists are still doing studies to get concrete evidence of the effects of tea on health.