Someone asked a week or so ago about Vietnamese tea. I don't know very much about it, but what I do know is that most of the tea drunk in Vietnam proper is flavoured tea. Most popular are a jasmine tea "Saigon tea" that is reminiscent of the Chinese yellow-box tea, and a distant second is lotus tea "Hue tea" or "tra sen" which my wife describes as tasting like rotting flowers.
I rather like both of these, and both of them are made from cheap commodity tea with flowers added to it. I don't know about pesticide use (although given the economic necessities I would doubt there was very much), and I know really nothing about higher grade teas from Vietnam.
I will say that I recently tried the "Vietnam Orange Pekoe" from Uptons and was very impressed. It had a strong flavour almost reminiscent of clove, but clearly not eugenol/clove itself. Very aromatic. I know a lot of folks turn their nose up at anything with an OP marking on the box, but I urge you to try this. It's only a couple bucks and I think it is a fine drinking tea at an excellent price.
--scott