How is Karachi to live?
A writer once said about Karachi, "The richest city of Pakistan where the largest number of poor people are living" A city which is providing bread and breakfast to more than 20million people daily is majestic A city which will welcome you no matter from where you are

How are the people?
Good As far as you don't disturb anybody nobody is going to do anything to you. The people differ, there are educated as well as ignorant people. You gotta be careful when you interact with someone, you should keep his/her background and level of understanding in mind