Processor: It has been upgraded from the 4S's Apple A5 to the Apple 46, which is 22 percent smaller and up to twice as fast as the A5.
Resolution: 1136 x 640 pixel resolution on the iPhone 5, compared to 960-by-640 resolution on the 4S.
The bottom line: If faster downloads and technical upgrades are important to you, then you might want to consider getting the newest version. Which will you opt for: the iPhone 5 or the iPhone 4S? If you're a 4S owner, do you think it's worth it to upgrade? If you don't own an iPhone, will you spring for the iPhone 5?