Pros
I started as a seasonal member for the holiday season, I found that management had a very good grasp of what needed to be done and what they wanted to get out of their seasonal team members. The tasks that were assigned on a daily basis were relatively easy to learn. The training process for tasks that require a higher level of competency was very structured and it is not difficult to be able to grasp the concepts rather quickly. There is an excellent level of support through store communication and tasks that might be outside your assigned area are easily found out about. There are always team members within communication reach and you are never truly "on your own."
Cons
Really, the downsides to Target are the same as any other retail store. You will have your share of irate and upset customers, and it is good to remember that the actions that customers perform are not aimed at you, personally. It is also good to let things slide by if necessary. You will always have to keep an eye out for the occasional shoplifter and the occasional strange behavior. Besides that, the other downside is that when you first start, the pay isn't that great. I started at minimum wage, but I also got a lot of hours, so it added up.