Pros
Learn managerial tasks, keyholder, prepare deposits. You can use your experience in doing tasks a retail manager does to leverage that into a manager's position at another company. You can get bonus commission or "PM's" for selling certain products, but that only works if you are in a store with enough traffic and people with money willing to buy expensive health products.
Cons
I got about $9 an hour to do everything a manager does including opening and closing the store by myself, attending mandatory conference calls, talking to brand/product salesmen, taking the deposit from the register to the bank, counting the money in the register, etc. I was not made aware that cocaine dealers use a GNC powdered vitamin to cut their product, so on SEVERAL occasions I was completely alone with no cameras to witness stuff happen to me with cocaine dealers hitting on me and buying this powder. People also use GNC products to pass drug tests, but if they tell you that is what they are using it for, you are not allowed to sell to them. This angers people very much. Again I was completely alone with no cameras to deal with that fact.