Pro Personal unlock codes
You can give out personal codes which will unlock the door, and you can have an unlimited number of these codes. However, if you don't have the optional wireless keypad ($79) each user will need to download the app and enter their code there. These codes can be configured to have a time duration where they will expire, or they can be permanent.
Con Wi-Fi requires additional hardware
With just the Smart Lock itself, the range is limited to Bluetooth, which means you need to be physically close to the lock. To control your lock using Wi-Fi (range is unlimited as long as you have internet access), you will need to purchase additional hardware (August Connect which costs $79, or an Apple TV which costs $99). These act as an in-between device, using a bluetooth signal to communicate with the lock and using Wi-Fi to connect with your phone.