Nike have released a new free app called Nike+ Move that takes advantage of the iPhone 5S's M7 Motion co-processor. This piece of hardware's sole job is to collect sensor data from integrated accelerometers, gyroscopes and compasses and offload the collecting and processing of this sensor data from the main central processor.
Nike's app is a gorgeous way of displaying this data in the form of their fitness format - NikeFuel. This is the same metric they use with their Nike FuelBand product and what I use to use with the Nike app back in the day with a wireless chip in the shoe and then again with the iPod Nano's pedometer capabilities.
Being an iOS app it also takes advantage of Game Center and can use this to show Local Leaderboards as well as the friend connection (Top Movers) from the Nike+ account. What's even cooler is Nike have an API for the Nike+ accounts, which means you can use this data in anyway you see fit - ala home dashboard.
All and all Nike+ Move is a must if you have an iPhone 5S and I look forward to more improvements and more importantly, more stepping in the future.