Concerning "The Lottery," I'll interpret "pros and cons" to refer to the story itself, and how it is written.
The pros are easy. Jackson uses a detached, limited point of view to present normal people in a normal environment. Her use of point of view and setting and plot combine to establish the normalcy of the town and the people. This sets up the reader for the surprise ending. But, the ending makes complete sense because of her use of foreshadowing. She avoids hints, which might allow some readers to guess the outcome, and which suggest the narrator wants the reader to guess the outcome (which would be disastrous to the success of the story). Yet, she does foreshadow, so the ending seems legitimate when it does occur. For instance, the boys collecting stones early in the story seems normal when read, but also legitimizes the ending once it occurs. It also adds to the horror--children are used to prepare the weapons by which the scapegoat/victim will be killed.
The cons are more sparse. Some have said that the ambiguity in the story is too great, that Jackson has not left any keys to aid in interpreting her parable. In other words, what is the target of the story? Is she attacking Nazi policies in WWII, tradition, scapegoating, witch hunts, the psychological tendency of normal humans to engage in abnormal behavior when that behavior is sanctioned by their peers, etc.?
This ambiguity is probably the most often mentioned weakness of the story. At the same time, one could also cite it as its greatest strength, and one of the reasons it is so often read and anthologized.
I can only hope that you are not referring to the actual lottery system that Jackson describes. I am not sure I see any pros in that setup! In terms of assessing Jackson's story, I see many pros and few, if any, cons. I love how she is able to construct a setting where one really gets to see what political theorists like John Stuart Mill describe as "the tyranny of the majority." She is able to construct a setting a small town, and through exquisite use of language develop an emotional framework or sensation where one knows something is wrong, yet is slowly and more increasingly horrified as to what is actually created in the process. The notion of one person "winning" this lottery is brutal, as it reflects how the collective voice can be a destructive one. I think that the social and political implications of the story are powerful ones.
I'm not exactly sure what you mean by the pros and cons, so I'm going to interpret this as the beneficial and negative effects of the story. Jackson's story is largely a critique of blind tradition and the lengths that people will go to in order to maintain their traditions. In "The Lottery," the people do not even remember when the lottery was started or for what purpose. However, they continue the ritual simply because it is something that they have always done. "The Lottery" has the beneficial effects of causing people to consider the nature of tradition and to evaluate its purpose in our lives. Do we hang on to traditions that are harmful to our society? On the other hand, such a critique may cause harm if it leads people to blindly assume that all traditions are harmful and worthless. Although the story does not necessarily suggest this, a reader may reach this interpretation anyway.