The previous thoughts were quite right in suggesting that political beliefs have much to do with this. Some argue that extreme interrogation can be a very precise manner of gaining intelligence and information. This is the fundamental position of the pro side. It continues to extrapolate that if one knew that a suspect had information that could stop an attack of some kind and time was of the essence, extreme or "enhanced" interrogation techniques could be used to procure such vital information, helping to save many lives. On the other hand, there is little to indicate that the more a person is beaten, the more valuable the information results. There is little to indicate that this is a direct correlation: The greater a degree that suspect is beaten, the greater of value information is revealed. On many levels, the suspect might simply be giving information that is useless in order to stop the beating. Additionally, some would argue that, especially in the American legal setting, the 8th Amendment to the Constitution does forbid "cruel and unusual" punishment and such techniques move law enforcement close to a precarious Constitutional line that really should not be broached. At the same time, there is a level of losing moral and political stature when the nation that has long stood for humane treatment of even its worst embraces techniques that go against such a principle.
This, of course, depends a lot on your political beliefs. At least it does in the US right now.
I think the pro of this is that it might (people argue about this and you hear both sides) get the people who are being interrogated to give up more information more quickly than they otherwise would. This could be very important if we need to get that information quickly.
To me, the biggest con of it is that it risks the moral standing of the nation that uses it. Countries like the US claim power in part because of their morality. When we condone actions that seem immoral to many people, we lose our legitimacy in the eyes of the world.