For me, the best feature is the log analysis with Azure Monitor's Log Analytics. Without being able to analyze the logs of all the activities that affect the performance of a machine, your monitoring effectiveness will be severely limited.
Azure Monitor offers stability and scalability for monitoring cloud environments, ensuring seamless integration with Microsoft platforms. Its customizable alert system and log analytics offer insights, aiding in system health maintenance. While powerful, integration with non-Microsoft systems, complexity of setup, and a data-size based pricing model call for improvement. Enhanced features, like AI event correlation and better third-party connectivity, could elevate its functionality for hybrid environments.