Both iM1 and Connected by August allow you to control your home with Apple HomeKit, but there are a few differences.
The iM1 Module only supports HomeKit and does not have support for virtual keys, Amazon Alexa, Google Assistant, Airbnb, HomeAway or DoorSense. You manage the iM1 module using the home app and the Yale Secure app – this is great for someone that is a very apple oriented family or home. It also does not support Auto Unlock on Arrival.
The Connected by August Kit allows you to integrate your Yale lock to HomeKit and mange it though the August app – because the August app has support for both iOS and Android it is a better app for a house with multiple technologies of phone.
Connected by August also gives you additional features such as Auto Unlock, Amazon Alexa and Google Assistant integration, DoorSense, and much more.