What are the pros and cons of Big Brother in 1984?
A pro of Big Brother and total government surveillance would be safety. In a world where everything is monitored and the police can even monitor your thoughts, violent crime would be almost non-existent. Tom Cruise's Minority Report focused on that kind of idea.
Big Brother also creates a huge uniformity of the population, so anything that doesn't fit the mold is easy to spot and "fix." That's what happened with Winston, although the fixing solution for him was really gross.
Another pro of Big Brother is how organized everything was. Nothing was out of place and there wasn't any extra stuff to get in the way of that organization and efficiency. Even the language itself was being streamlined.
Cons on the other hand are that Big Brother essentially wipes out any independent thought or individualism. To an American that is horrible since the Bill of Rights basically guarantees individuals the right to think what they want to think, and at times do what they want to do.
Another con is that there is no motivation for self improvement. Orwell's 1984 created a sort of caste system of society. Winston was what he was, and had no real hope of becoming more. A society with no motivation to do better is a dying society.