Pros
The people you work with tend to be friendly and fun to be around. The drinks are wonderful and ever changing. The hourly salary, while just above minimum wage, is acceptable thanks to the shared tips. (I usually got about $20 extra a week in tips.) It's great for people who really love meeting others and getting to know them. It's all about the personal connection with customers. At the same time, once you get acclimated your coworkers become like a family. The benefits are also good including 1 "markout" (bag of coffee, box of tea, etc) every week and an employee discount on everything else.
Cons
The patrons of Starbucks tend to know exactly what they want. As a barista in training, they pile on a TON of recipes and words and drink names and it can be overwhelming. However, I experienced many customers who were very frustrated that I wasn't not perfect. (Likewise, there were understand people as well.) There is a lot of pressure to learn everything quickly and well and in my experience I was reprimanded for every small mistake (which doesn't make for a happy employee). Obviously it's a coffee shop so it's open really early and when you have to be there at 5am multiple days in a row, it can really get to you. My biggest issue with Starbucks is that, as a whole, they do not allow employees to request time off. As a college student, I needed that opportunity. (In their defense, usually you would have the same hours every week so it should be easy to plan around it. My store was understaffed because of low turnover.)