The best tea is the one you enjoy most. That said, a lot of higher quality loose leaf green teas are going to be sourced directly from the actual tea factories and farms in China or Japan. While finding reputable vendors that airfreight fresh teas isn't necessarily difficult, getting the right quality that you like can sometimes require either a bit of trial and error, or trusting someone's recommendation. Exploring the world of tea is part of the enjoyment of it all, in my opinion!