Pros
It is a rewarding and fun place to work. Promotes basic customer service and friendliness and also allows you to grow personally. I really like how Baristas are given the privilege of doing things that usually require a supervisor to do (i.e. mark out drinks for yourself or dissatisfied customers, give refunds, etc). I feel like I am trusted and equal to my peers.
Cons
Inconsistent scheduling (especially with new "optimized scheduling" system). Aside from HAVING to work at least 15 hours a week, the hours and basic schedule you get each week varies greatly. Starbucks is not huge into promoting from within, and I have seen on multiple occasions, people get promotions that did not deserve them, or vis versa. Also, the vertical management style really makes it difficult for everyone (even store managers) to establish policies that are best for the individual business (i.e. not being allowed to brew decaf coffee after 12 PM as a cost cutting measure handed down from corporate, even though my store is next to a retirement home and most of our customers wanting brewed coffee in the evening want it decaf).