the difference ? drying , ive seen ounces of top quality bud go sh*t because it was dried too quickly reducing strength or not enough ventilation resulting in mould, telling the difference between good and bad bought gear is experience smell can be a good indicator but ultimately smoke it see what the effect is ,use the same rules that you would apply to buying any (expensive) product a bit of common sense and caution these are drug dealers you know ah ah.keep tokin