The pros of hydraulic fracturing (or fracking) are largely economic and political. The cons are generally environmental. Neither the pros nor the cons are completely certain to come about.
The pros of fracking have mainly to do with the fact that fracking is likely to produce a tremendous amount of natural gas in the United States. This has two main good points. First, it allows the US to move towards energy independence. This means that the country would not have to rely as much on imported oil from places that are politically unstable or even hostile to the United States. Second, it would mean more prosperity and jobs. The natural gas industry is booming and will boom more with more fracking. This is a good thing, economically speaking.
The cons of fracking are generally environmental. Fracking does, without a doubt, use tremendous amounts of water. This can be problematic at a time when water supplies are starting to dwindle in some parts of the country. There are also possible, but not proven, negative environmental effects of the process. It might lead to the leaching of fracking chemicals into ground water. It might even cause earthquakes. It might lead to the continued use of fossil fuels which would contribute to global warming.
Thus, the cons are mainly environmental while the pros are mainly economic and political.