Pros to curing cancer: One of the most dreadful and horrible ways that has plagued mankind since the beginning has been cured.
Cons to curing cancer: Pharmecudical companies will suffer... oh well there is always AIDS.
Pros to seducing women at will: You could knock up Megan Fox and have that shit on lock. Because it doesnt make sense to just seduce Fox.
Cons to seducing women at will: You could die of dehydration.