IOS 7 vs. KitKat: For IOS 7, you can command to Siri to read the message out loud if you are too busy to read. Google on the other hand can recognize 50 voice commands and it also has Moto X that recognizes, OK Google to bring up Google now.
Who wins: Kitkat wins since it can even answer questions about Sports and some general trivia. It is possible to ask questions that encourage conversation as well. It can also accomplish the usual voice commands like sending messages or asking for locations.