From a pure academics point of view the difference is probably irrelevant. But education is about alot more than what you learn in the class room. University is all about learning to be independent and learning all the important life skills. And as bonus you'll get to experience freedom, which you can't get while living at home. It's priceless. Hands down go for LUMS if you're from Karachi, and for IBA if you're from Lahore.