Pros
AT&T will hire you without prior sales experience. The base pay and commissions are good. Benefits are excellent if you work at a corporate store. They are unionized.
Cons
You will be shown training videos that tell you to always act in the customers' best interest and never upsell them on things that won't help them or hide upgrades within a rerate. However, in practice, these are precisely the things that you will have to do to meet your quotas for upsells on things of dubious value to the customer (e.g. AT&T's cloud storage instead of iCloud) or dual-line phone plans for people who in reality do not use that much hotspot to begin with or are not business people who would benefit from a second line. Yet you flog that multi-line discount and present it as a cost-saving move. Put new phone installments on that new line so they can't get rid of it without lump-sum paying off the phone. Shady stuff like that is how you get ahead. However, if an aggrieved customer should unthinkably find issue with these things after the fact, then you are on the chopping block. So you will find yourself between a rock and a hard place (and perhaps a guilty conscience).