Examine.com explains the different processes and advantages to our common tea options. As always their posts provide the scientific support references. My summary would be:
Most Teas we drink are are derived from Camellia Sinesis (green, black, white, oolong and pu-erh).
Catechins are flavonoids which carry the most of the health benefits
White tea tends to be higher in catechins by weight, but when content is equal green tea has more anti-oxidant potential.
Overall, green tea is the ‘basic’ tea that is enzymatically inactive and non-oxidized. White tea and Oolong tea are partially oxidized, but Oolong is still enzymatically active. Black tea is fully oxidized and enzymatically active. Pu-erh tea is fermented and quite unique from the other teas.