One of the biggest differences between the iPhone 4 and iPhone 4S is Siri - Apple's 'virtual assistant' that responds to your voice commands and completes tasks for you, such as texting someone, or scheduling a calendar entry.
Sure, Siri may not be as fast or precise as what is shown in Apple's ads, but it still performs the functions it is said to do. You may have to repeat yourself here and there, or annunciate a bit more, but it's not totally broken for everyone. The man wasn't obligated to purchase or upgrade to an iPhone 4S. If it doesn't work for you, return the phone, and get an iPhone 4. Money and time saved across the board. Filing a lawsuit against a gigantic corporation because your phone didn't text for you is just silly.