Bulk is the preferred method of taking herbs, the patient is instructed in how to prepare the formula and then cooks their formula and then normally divides by 3 for the daily dose. More powerful some believe but it is also time intensive.
Powders are bulk herbs that have been processed to be more convenient for the patient. It allows the Acupuncturist to customize your formula for you. You normally take 6 - 8 ounces of hot water, mix the appropriate amount of powder and drink as an herbal tea.
Patents are formulations that are made by a manufacturer such as Plum Flower, Evergreen Herbs or Golden Flower Herbs. They generally contain more herbs than a custom or traditional formula and are designed to treat a broader category of patients. They are easy to administer for the practitioner and take for the patient. They come in capsules, tea pills (think black bb's) and tablets.
What do you prefer?