The logical choice for you would be AFA, mainly for two reasons:
- AFA is located in San Francisco, so the product will likely arrive at your door quicker.
- ADG sells 9L bag of amazonia for $47.95/bag (with free shipping), and AFA sells the same product for $30 with approximately $15 shipping (i used a random seattle zipcode to calculate the cost, so your mileage may vary slightly). You'd probably save a few bucks by going with AFA.
Since vendor reviews are not allowed, it is best not to discuss which one is better.